bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Surface Roughness on R19 Steel Using PIN on Disc Apparatus
Authors: Pradeep M. , Vignesh Packkirisamy , Arun M. , Durairaj M.
Published: July 2014

Influence of surface roughness on coefficient of friction of Titanium coated R19 Steel is investigated in this paper using Pin on Disc Apparatus. Wear properties of R19 Steel are evaluated because it is widely used in making the rail wheel and rail roads over the years. Titanium coating of 100nm thickness was deposited on the R19 Steel by Electron Beam Gun Physical Vapor Deposition method. Wear and friction parameters were evaluated using Pin on Disc apparatus. The Surface morphology plays an important role in affecting the wear rate. Non-contact surface roughness tester was used to examine the surface texture and measure the surface roughness of the specimens. The test was carried out in a pin on disc apparatus for Normal Load of 15N, Sliding Velocity of 3m/s and Time 5 min. The texture and the roughness parameters of the surface affect the coefficient of friction. The experimental values of roughness parameters of uncoated and coated disc and its effect on coefficient of friction are compared and validated. Results show that the Coefficient of friction decreases with lower value of Ra. Lower values of frictional force and coefficient of friction results in lower wear rates.
Variation in Residual Stresses due to Thermal Cycling Induced on the Hardfaced Grid Plate in PFBR
Authors: Balaguru S. , Saranraj K. , Murali Vela  , Chellapandi P.
Published: July 2014

In sodium cooled fast breeder reactors, the high operating temperature necessitates hard facing of grid plate to avoid galling and to reduce the wear loss of the base material . Nickel-base cobalt-free alloy called Colmonoy-5 has been chosen as the hard facing material for the Prototype Fast Breeder Reactor (PFBR) grid plate. The grid plate (GP) which is a critical component made of 316 LN SS that holds the core subassemblies are hard faced, to prevent galling and also to minimize wear caused by subassembly insertion/removal and erosion due to high sodium velocity at 670 K. Thermal cycling of hard faced circular grid plate made by Plasma Transferred Arc Welding (PTAW) generates residual stresses due to differential shrinkage of the molten deposit and difference in coefficients of thermal expansion between the deposit and substrate material. In this project the effect of thermal cycling of a nickel-base hardfacing alloy deposited on an austenitic stainless steel grid plate was studied. Finite element analysis of hard faced circular grid plate is performed for obtaining residual stress which includes elasto-plastic analysis. Coupled thermo-mechanical analysis is done for thermal cycling of hardfaced circular gridplate to quantitatively estimate the residual stress.
Assessment of a Complex Aerospace Design through Optical Techniques
Authors: Swain Digendranath , Philip Jeby , Pillai S. Annamala
Published: July 2014

This paper reports the design assessment carried out on a subassembly of an advanced rocket using experimental techniques. The design was very complex and critical, since a cylindrical shell had a square cutout on the axial-hoop plane interacting with a notch in the axial-radial plane. Herein, two optical techniques have been employed for assessing the interaction between the notch and the cutout, and their individual contributions to the strain-field. Initially, a photoelastic model was studied to estimate the stresses at the notch tip. Subsequently, DIC was employed for measuring strains at the notch during the ground based testing of the actual component. The outcomes of these two experiments showed that the effect of the cutout to the strain concentration was negligible due to the extra stiffness provided by other assemblies.
Comparison Study of As-Cast and T6 Condition of Microstructure, Bending Strength and Double Shear Strength of A356 Alloy by Gravity, Vacuum and Squeeze Casting
Authors: Sekar Kannan , Kanjirathikal Allesu , Joseph M.A.
Published: July 2014

The hardness, bending strength, and double shear strength of A356 aluminium alloy was studied under as cast and T6 heat treatment conditions obtained with gravity casting, vacuum casting and squeeze casting methods. The results of these three casting methods have been compared. The hardness, bending strength of A356 alloy after T6 obviously increased; the hardness value of both vacuum casting and squeeze casting has been found to be 62 HRB which is relatively high compared to gravity casting. The bending strength of gravity casting is 299 MPa (22% increase) compared to vacuum casting. However, after T6 heat treatment, the double shear strength values of all these three castings decreases.
Design Modification in Special Purpose Machine by Introducing Poka-Yoke Techniques
Authors: Venkatesh G.V. , Prabhu J. Samuel Arul Doss , Kanimozhi B.
Published: July 2014

This paper mainly comprises of design and fabrication of torque value check by using pneumatics as a base concept. The machines which detect the play of the wheel end which is placed in the steering column for converting the rotational motion to angular motion of the tyres. The torque meter which displays the play of the wheel end through a digital output. Since the customers prefer their own specification there is a chance of misplacement in the batch production. The steering column manufacturing unit faces a serious crisis. In order to overcome this Japanese technique called Poka Yoke (error proof) has been infused with this design. The Programmable Logical Circuits (PLC) controlled unit which plays the vital role in the sequencing the pneumatic cylinders according to operations planned. The sensors placed in the proper orientation helps the worker to detect the error in the work piece. With this an additional printer device is installed which automatically prints the label code for the product. The sensor allows the operator to paste the label in the correct position. If the label is positioned in the wrong place the led emits red light to glow or the green light glows which indicates the part is correct.
Investigation on Eddy Current Braking Systems – A Review
Authors: Anantha Krishna G.L. , Sathish Kumar K.M.
Published: July 2014

The changing magnetic field will induce eddy currents in the conductor. These currents will dissipate energy in the conductor and generate drag force. It is found that Aluminium is the best material as conductor compared to Copper and Zinc. Also, it is found that the larger thickness of disc, more number of turns of electromagnet and higher electrical conductivity of conductor influences the generation of greater braking torque. Conventional braking system relies on adhesion force between rail and wheel. It is found that a brake built up from permanent magnet pieces that combine both magnetic rail brake and eddy current brake permits the most profitable braking action through the whole range of acceptable speeds. Permanent magnet eddy current brake uses Neodymium - Iron - Boron (NdFeB) magnets. The analysis of permanent magnet eddy current shows that the parallel magnetised eddy current topology has the superior braking torque capability. In electrically controlled eddy current braking system subjected to time varying fields in different wave forms, the triangular wave field application resulted in highest braking torque. Electromagnetic brakes were found to interfere with the signalling and train control system. Permanent magnet eddy current brakes are a simple and reliable alternative to mechanical or electromagnetic brakes in transportation applications. Greater the speed greater is the eddy current braking efficiency. Hence, author intends to work on the development and investigation of permanent magnet eddy current braking system.
Load Distribution in a Rolling Element Bearing under Dynamic Radial Load
Authors: Govardhan T. , Choudhury Achintya , Paliwal Deepak
Published: July 2014

External load in a bearing is transferred from one race to another race through the rolling elements. In the present work, an investigation has been made to estimate the load on a rolling element in a bearing subjected to dynamic loading. The dynamic loading, in the present study, included harmonic and periodic loadings which are deterministic functions of time. The roller load is also investigated under random loading with known statistical values of mean and variance. Numerical values have been obtained for NJ204 bearing with known radial clearance. These results show the variation in the spectra obtained for different nature of external loadings. These results can be expected to satisfy the difference in theoretical and experimental spectra obtained by earlier researchers.
Low Cycle Fatigue Analysis of after Treatment Device Induced due to Thermal Load by Using Finite Element Analysis
Authors: Kumbhar Swapnil Vitthal , Kulkarni Vilas , Tayade R.M.
Published: July 2014

Cyclic thermal loading causes cyclic thermal stress and thermal fatigue in the component. The goal of this paper is to characterize the thermal fatigue behavior of after-treatment (AT) device, i.e. Exhaust Gas Processor (EGP) and prediction of crack initiation cycles. The paper contains transient thermal analysis to map temperature on EGP model. By taking temperature distribution as input, Elasto-plastic structural analysis is done. Based on stress-strain data and fatigue material property, crack initiation cycles are estimated. For low cycle fatigue analysis, strain based approach, i.e. Brown-Miller Criteria with Morrow mean stress correction factor [1] is used. The von-Mises stress and crack initiation cycles are investigated and S-N curve and Ɛ-N curve are compared with standard graphs.
Mechanical Behaviour and Energy Absorption Foam Filled Structures of Square Section under Compression Loading
Authors: Rajak Dipen Kumar , Kumaraswamidhas L.A. , Das S.
Published: July 2014

The focus of this paper is to study the energy absorption characteristics of aluminium foam filled sections. The energy absorption capability of square mild steel foam filled and empty samples to absorbed mechanical energy have been estimated according to the results from the compressive tests. The tests were performed on the universal testing machine .The experimental results shows that aluminium foam filled sections feature have good energy absorption at various strain rates from 10-3/s to 10/s.
Multiscale Analysis Approach to Find the Dynamic Characteristics of Graphene Sheet
Authors: Gajbhiye Sachin O. , Singh Satinder P.
Published: July 2014

The research work addresses question on dynamic characteristic of structure which exhibit periodicity at nanoscale viz. single layer graphene sheet using multiscale analysis approach. The carbon-carbon bond of graphene sheet is modeled as space frame element whereas the carbon atom is modeled as 3D-mass element without rotary inertia. Molecular structural mechanics (MSM) model has been used to find the equivalent geometric and elastic properties of space frame element to represent carbon-carbon bond. In molecular structural mechanics model, force field is expressed in the form of steric potential energy by omitting the electrostatic interaction. Sectional stiffness parameters are linked with the force field constants to derive the equivalent elastic and geometric properties of space frame element. This approach is used here to investigate the dynamic behavior of single layer graphene sheet. Simulations have been carried out with different values of aspect ratio to know the effect of variation in length and width on the natural frequencies of graphene structure. Molecular dynamic simulation has also been carried out on the same structure of graphene sheet to validate the results of proposed molecular structural mechanics model.
Densification and Consolidation of Al 5083 Alloy Powder by Equal Channel Angular Pressing
Authors: Gudimetla Kondaiah , Chaithanyakrushna B. , Chandra Sekhar K. , Ravisankar Balasubramanian , Kumaran S.
Published: July 2014

In this present work the elemental powders pertaining to composition of Al5083 alloy was milled using planetary ball mill (Insmart systems) for 20 h. The elemental powders are loaded in HSS vial with 10:1 ball to powder ratio at 250 RPM. Various parameters such as crystalline size, particle size and morphology have studied using X-ray diffraction analysis and scanning electron microscopy. The crystallite size of the powders determined using Williamson Hall analysis of XRD is 23 nm after 20 h of milling. These nanocrystalline Al-5083 alloy powders were consolidated using ECAP with and without application of back pressure. Physical and mechanical properties such as density and hardness values were measured for sintered and unsintered samples.
Stress Intensity at the Initiation of Instability by R Curve
Authors: Sundaresan S. , Nageswara Rao B.
Published: July 2014

The life expectancy or failure of aerospace pressure vessels is evaluated by the critical stress intensity determined by the crack growth resistance curve of a material. Load versus crack mouth opening displacement data is generated from the Compact Tension specimens made from the weld joints of maraging steel rocket motor segments. The steps involved to generate critical stress intensity factor is explained. A power law is adopted to model the crack extension in terms of stress intensity factor and determine the maximum failure load of weld specimens. Maximum failure loads of CT specimens obtained by test and analysis are presented.
Mechanical and Tribological Properties of the Composition “Steel - Nanostructured Surface Layer of a Material with Shape Memory Effect Based TiNiCu”
Authors: Blednova Zhesfina , Rusinov Peter Olegovich
Published: July 2014

The results of a study of the effect of the composition "steel-nanostructured surface layer of a material with shape memory effect TiNi, TiNiCu" on wear-fatigue characteristics of the samples are reported. Formation compositions performed by plasma spraying and high-speed flame spraying. Experimental studies have shown the efficiency of the developed technologies.
Modeling and Optimization of the Wear Performance of Aluminium Metal Matrix Composite Using Response Surface Methodology
Authors: Ganesh R. , Neshan D.K.S. , Rajendra Prasad K. , Kesavan Chandrasekaran
Published: July 2014

In the present study, wear performance of Al 2219-SiCp composite was investigated and the process parameters were optimized and modeled using Response Surface Methodology (RSM) technique. In the development of the model, weight fraction of the reinforcement, sintering temperature, applied normal load on the pin and disc speed were considered as model variables. Full factorial experiments were carried out and observed wear characteristics were taken as input for the model. The results exhibit good prediction accuracy of about 85% on average of all wear characteristics and percentage error was within the acceptable limits.
Performance Comparison of Partial and Full Textured Thrust Bearing Operating with Non-Newtonian Lubricant
Authors: Yadav Saurabh Kumar , Sharama Satish C.
Published: July 2014

The present paper theoretically investigates the influence of partial and full texture on the performance of the hybrid thrust pad bearing operating with non-Newtonian lubricant. The presented results show that the dilatant lubricant with partial textured surface has the maximum load carrying capacity. The effect of full texture on hybrid thrust bearing is positive. In the present paper, Finite element method with Reynolds boundary conditions is implemented. The comparative study shows that partial texturing in the bearing significantly works better than the full texturing and the friction coefficient in the bearing can be reduce upto 60% as shown in the results.
Development of Viscosity Based Correlation for Estimation of Higher Heating Value (HHV) of Diesel Fuel
Authors: Khairnar Lokesh Ashok , Dhamangaonkar Pradyumna R.
Published: July 2014

Estimation of higher heating value (HHV) is one of the basic step in performance modeling and calculations of thermal systems. The HHV of liquid fuels is determined experimentally, which is time consuming and expensive. From literature survey it is observed that the HHV of most of the liquid fuel is a function of viscosity. In this paper an equation is developed for samples of diesel fuel. The HHV calculated using equation for samples using viscosity show average difference of 0.06255% for diesel fuel. For unknown diesel samples the equation shows satisfactory agreement with the experimental results. This equation can be used to predict HHV of unknown diesel fuel by knowing its viscosity.
Development of Al-TiC Metal Matrix Composite by In Situ Reaction
Authors: Kumar Aravind K. , Balasivanandha Prabu S.
Published: July 2014

This study reports the development of Al-TiC metal matrix composites with 2.5 % of TiC is developed using in-situ route by the reaction of carbon powder and halide salt K2TiF6 with the aluminium melt. The composites were fabricated using stir casting process by varying three different factors such as temperature, addition time and holding time. The experimental trials are decreased using L9 Orthogonal array in taguchi design. The prepared composite specimen was characterized using XRD, hardness, and Microstructure examination using optical microscopy.
Development of Guided Wave Ultrasonic Inspection Method for Thick Composite Structures
Authors: Saikrishna U. , Srinivas K. , Prasad Y.L.V.D.
Published: July 2014

Ultrasonic Non-destructive testing is a well known technique for inspecting fiber reinforced composite structures however; its capability is severely limited by the high attenuation in thick and multi layer structures. Guided wave ultrasonic inspection has been reported to be useful tool for quantitative identification of composite structures. It takes advantage of tailoring / generating desired ultrasonic wave modes (Symmetric and anti-symmetric) for improved transmission through the composite structure. For this, guided waves have to be generated selectively by precisely placing transducer at an angle to the test surface. Automation of two axis fixture for transmission and reception of transducers have to be used for avoiding manual errors. The captured signals have to be processed in order to extract useful information from the received ultrasonic signals. The proposed project aims at developing automated guided wave inspection methods along with digital signal processing for generating dispersion curves for thick composited. Using test laminates with implanted defects, methodology for thick composite inspection with guided wave ultrasonic’s will be established. For this data will be captured and analyzed using Labview software.
Experimental Investigation and Performance Evaluation of a Multi Turn Closed Loop Pulsating Heat Pipe
Authors: Babu N. Narendra , Naik Rudra
Published: July 2014

Pulsating heat pipe (PHP) is a passive heat transfer device, which transfers heat from one region to another with exceptional heat transfer capacity. It utilizes the latent heat of vaporization of the working fluid as well as the sensible heat. As a result, the effective thermal conductivity is higher than that of the conductors. An experimental study on three turn closed loop pulsating heat pipe with three different working fluids viz., Acetone, Methanol, Heptane and distilled water were employed. The PHP is made up of brass material with an inner diameter of 1.95mm, with a total length of 1150 mm for different fill ratios (FR) was employed .The PHP is tested for the thermal resistance and the heat transfer coefficient. The experimental result strongly demonstrates that acetone is a better working fluid among the working fluids considered in terms of higher heat transfer coefficient and lower thermal resistance.
Experimental Investigation of Four Stroke Diesel Engine Performance Using Neem Oil and Neem Oil with Hydrogen as a Fuel
Authors: Rajasekaran Thangaraju , Duraisamy K. , Arvindd K.R. , Thamilarasu D. , Venkatachalam Chandraprabu , Suresh S.
Published: July 2014

Depletion of fossil fuels, unaffordability of conventional fuels (petrol, diesel) and atmospheric pollution lead researchers to develop alternative fuels. Fuels derived from renewable biological resources used in diesel engines are known as biodiesel. Biodiesel is environmental friendly liquid fuel similar to petrol and diesel in combustion properties. Increasing environmental concern, diminishing petroleum reserves and agriculture based economy of our country are the driving forces to promote biodiesel as an alternate fuel. Hydrogen seems to be viable fuel to meet sustainable energy demand with minimum environmental impact. Hydrogen has high calorific value and clean burning characteristics which makes it effective fuel for future. It was found that hydrogen usage reduce emissions such as CO2 and HC. India is one of the largest producers of neem oil and its seed contains 30% oil content. It is an untapped source in India, so the neem oil usage will be a best option. The investigation made on pure neem oil and neem oil with hydrogen addition at different flow rate (2 lpm & 4 lpm) in CI engines. The result shows that, brake thermal efficiency of neem oil with 4 lpm hydrogen was increased to 7.98% compare to pure neem oil at 4 Nm torque and fuel consumption of neem oil with 4 lpm hydrogen was decreased to 13.49% compared to pure neem oil at 4 Nm torque.
Experimental Investigation on DICI Engine by Using Chemical and Nano Additives Blended Biodiesel
Authors: Arun R. , Rao Muthe Srinivasa , Prabu A. , Anand R.B.
Published: July 2014

An Experimental investigation is conducted to establish the feasibility of using Jatropha biodiesel in Direct Injection Compression Ignition (DICI) engines. While the biodiesel has certain limitations and adverse in terms of poor performance and high level of pollutants in the exhaust of the gases, specified chemical (Propylene Glycol, C3H8O2) and nano(Al2O3) additives are used with Jatropha biodiesel. The experiments are conducted in two phases by using an experimental test rig, which consists of a DICI engine, electric loading device, data acquisition system, and AVL exhaust gas analyzers. In the first phases of experimentation, the performance and emission characteristics of the engine are analyzed by using neat diesel and Jatropha biodiesel and in the second phase of investigation, similar experiments are conducted by using chemical and nanoadditives blended biodiesel. The results of biodiesel are compared with those of neat diesel and it is seen that the performance and emission characteristics of the engine are inferior in the case of biodiesel when compared with neat diesel. However, the results revealed that the working characteristics could be improved by selecting of proper chemical and nanoadditives in right proportions.
Development of Shape Memory Alloy Polymer Composite and Influence of Material Parameters on Shape Memory
Authors: Jithin C.S. , Prabu S. Balasivanandha , Velmurugan Ramachandran
Published: July 2014

The material development is aimed at utilizing a suitable Metal Alloy in combination with a most appropriate plastic material considering the achievement of desirable basic features of Smart materials like Shape Memory Effect, Flexibility, recovery time etc. In the present work shape memory composites were developed using Ni-Ti alloy as reinforcement into the epoxy matrix. To understand the recovery and the influence of the Young’s modulus of the matrix, three different combinations of epoxy and hardeners are used. This experiment has considered different combinations of Ni-Ti SMA wire spacing, Ni-Ti SMA wire orientations and Epoxy Mix proportions. The experiments are designed based on ‘Taguchi’s’ L9 orthogonal arrays. ‘Taguchi’s’ method combined with S/N ratio of analysis is used as the statistical tool for optimization of the most recommendable combination of the newly developed SMA polymer composite material. This is due to the special intention of finalizing the most advantageous product in view of physical properties, percentage shape recovery, recovery time etc.
Finite Element Analysis of Three-Fluid Heat Exchanger for Diesel Engine Exhaust Heat Recovery System
Authors: Veerabhadrappa Kavadiki , Seetharamu K.N. , Kembhavi Chethan , Dayanand Darshan , Vinayakaraddy Vinayakaraddy , Kumar Rupanagudi Suresh
Published: July 2014

In internal combustion engines, only a part of the fuel energy flow is transformed into power available at the crankshaft, while the most part of the fuel energy flow is lost as coolant, exhaust gases and other waste heat flows.The focus of this study is to evaluate the performance of three-fluid re-circulating type heat exchanger to recover energy from exhaust gas The cold fluid is re-circulated to enhance the recovery of heat from the exhaust gases. Finite element model of the heat exchanger is developed based on the detailed geometry and the specific working conditions and the effectiveness of the heat exchanger is computed. Non-Dimensional parameters are introduced which makes the analysis more versatile. The effectiveness is computed for different values of NTU, Heat capacity ratios, Overall heat transfer coefficient ratio between fluid channels and the inlet temperature.
Heat Transfer Studies on Condensation Using Heat Pipes
Authors: Singh Punit , Venkatachalapathy S. , Kumaresan G.
Published: July 2014

This experimental study finds the effect of condensation on the thermal performance of heat pipe. Condensation heat transfer rate, heat transfer coefficient and variation of temperature over the heat pipe are measured at vertical and horizontal position of HP, by varying the steam-to-surface temperature difference. It is found that the condensation heat transfer rate for vertical position of heat pipe with CuO nanofluid is 2.07 times higher than the horizontal position, whereas the increase in heat transfer coefficient is 1.94 times. Using CuO nanofluid instead of deionized water in the heat pipe enhances the heat transfer rate and heat transfer coefficient by 1.25 and 1.42 times respectively for the vertical orientation.
Investigation Analysis on the Performance Improvement of a Vapor Compression Refrigeration System
Authors: Madasani Ravi Chandra , Reddy Kappati Manikanth
Published: July 2014

The principal objective of the paper is to modify the conventional vapor compression refrigeration system by connecting heat exchangers thereby heating and cooling of water is done simultaneously. The vapor refrigerant is supplied to the hermetic sealed compressor where the refrigerant gets compressed to a temperature of 100-120◦ C. The compressor is connected to a counter flow heat exchanger. Experimentation is carried out to design and manufacture a modified vapor compression refrigeration system. The main parameters considered during the design are connection of a compressor to a hermetically sealed compressor, keeping polyurethane foam as insulating material, adjusting the capillary tube and finned evaporators. The operations carried during the fabrication of equipment are bending, brazing and arc welding process. After the experimental setup has been fabricated the system is checked for the performance by using refrigerants R-22 and R-407.The results are plotted between heating temperatures, cooling temperatures with respect to time in minutes.
Performance Evaluation of Diesel Engine Runs on Biodiesel Blending
Authors: Gopinath V. , Suresh P.
Published: July 2014

Diesel plays a very important role in rapid depletion of conventional energy sources along with increasing demand and also major contributors of air pollutants. Diesel is used in the present days for engines and the invention of an alternative or a blend to the conventional diesel seems very essential to the energy crisis. Major portion of today's energy demand in India is with fossil fuels. Hence it is high time that alternate fuels for engines should be derived from indigenous sources. As India is an agricultural country, there is a wide scope for the production of corn oil from the germ of corn (maize). In this experiment, an attempt has been made to investigate four types of fuels are considered 100% Diesel, 90% Diesel+10% Corn oil Methyl Ester, 80% Diesel+20% Corn oil Methyl Ester, 70% Diesel+30% Corn oil Methyl Ester and 60% Diesel+40% Corn oil Methyl Ester. The various performance parameters like, brake thermal efficiency, Mechanical efficiency and brake specific fuel consumption were measured and analyzed. In the experiment it found the biodiesel blends gives comparable performance to diesel.
Performance of a Direct Injection Diesel Engine Using Jatropha Diesel Blends as Fuel
Authors: Layek Apurba
Published: July 2014

Jatropha bio diesel blended with mineral diesel in proportion 2:1 by volume is used to conduct performance test and emission characteristics of a single cylinder direct injection diesel engine. Jatropha-diesel blend is used to perform engine performance and emission tests at variable loads & throttle settings (25%, 50%, 75% and 100%). Observed data were utilized to obtain various performance parameters such as brake power, brake specific fuel consumption, brake thermal efficiency at various loads and throttle settings. Simultaneously observations were also made to obtain exhaust gas temperatures and exhaust emissions (CO, CO2, HC and NOx). In existing engine diesel provides higher and economic power generating capacity for entire operating ranges but effect of varying load /throttle on performance behavior were fantastically similar. Reduced HC and NOx emission with the blend also better, highlights some positive aspects of combustion and allowance for higher compression ratio with the blend.
Short-Pulse Collimated Radiation in a Participating Medium
Authors: Padhi Biranchi Narayana
Published: July 2014

A two-dimensional model is presented in this article to study the transient radiative transfer phenomena involved in a participating medium subjected to short pulse collimation. The model assumes the medium bounded by diffusely emitting and reflecting boundaries, one of the boundaries is irradiated with a short pulse collimated beam. The finite volume method is applied to solve the transient radiative transfer equation governing the physical phenomena. The fully implicit scheme is used to discretize the transient term. In the proposed approach, intensity can directly be evaluated by solving the governing transient radiative transfer equation. The effects of scattering albedo and emissivity on the transmitted and reflected flux are studied. The performance of two different spatial schemes: STEP and CLAM are also been tested. It is seen that the CLAM scheme gives results to a greater accuracy and hence, correctly predict the speed of photon whereas STEP scheme over predicts the same.
Simulation Studies on Two-Dimensional Electronic Board with Multiple Non Identical Heat Sources
Authors: Tinnaluri Narasimha Suri , Pereddy Nageswara Reddy , Sastry Malladi R. Ch. , Murthi Pinjala Tejo
Published: July 2014

The present paper reports results of simulation studies on combined conduction – convection – radiation from two dimensional electronic board equipped with three discrete non identical heat sources. The three non identical heat sources are located across the board. The heat generated in the three heat sources is conducted across the board subsequently getting dissipated by convection and radiation. Air, a radiatively transparent medium, is considered to be the cooling agent. The governing partial differential equations for temperature distribution in the entire computational domain are obtained by appropriate energy balance between the heat generated, convected and radiated. The non linear partial differential equations deduced as above are discretized using finite difference method. The resulting algebraic equations are solved using Gauss - Seidel iterative method. A computer code in C++ is written to solve the problem. A thorough energy balance test and grid study has been performed to freeze on appropriate grid size. The effect of thermal conductivity, surface emissivity and convection heat transfer coefficient on local temperature distribution and maximum temperature distribution of the electronic board are demonstrated exhaustively. Keywords: Surface Radiation, Conduction, Convection, Electronic Board, identical Heat sources.
Temperature Prediction Methodology for a Missile Flying at Low and High Altitudes
Authors: Vijayakumar G. , Kachroo Ashwani Kumar
Published: July 2014

Missiles fly at supersonic and hypersonic speeds. Airframe forms the aerodynamic shape of the missile and houses several components essential for mission with suitable structural supports. The missile airframe is subjected to high rate of heating caused by kinetic heating due to very high vehicle speed. Heat transfer analysis of the missile airframe structure is required to be performed for wall temperature predictions to select the material of missile construction with suitable wall thickness and also to check design adequacy for ensuring the safe operation in the severe thermal environment experienced during flight. This paper describes the methodology of evaluation of heat flux distribution over missile wall, prediction of missile wall temperature distribution considering airframe as heat sink and validation of the methodology against flight data. Heat flux has been estimated using classical engineering methods for both stagnation as well as off-stagnation regions including the effect of angle of attack, rarified flow, thermal radiation and solar heating. Transient three dimensional heat transfer analysis with convective and radiative boundary conditions has been carried out for predicting the missile wall temperature profiles. Parametric study has been carried out, considering various parameters such as material of construction, thickness and time duration. The prediction methodology has been validated and a close match is observed between the predictions and flight data.
Theoretical Studies on the Application of Pulsating Heat Pipe in Vapour Compression Refrigeration System
Authors: Naik Rudra , Pinto Linford , Rama Narasimha K. , Pundarika G.
Published: July 2014

This paper proposes a simplified theoretical model of Pulsating Heat Pipe (PHP) employed in a vapour compression refrigeration system. The model developed is mainly based on well known physical equations and partially based on empirical correlation. The present theoretical investigation of PHP is focused to explore its suitability as a heat exchanger in the condenser of vapour compression refrigeration system. A parametric analysis is carried out to design the vapour compression refrigeration system with PHP as the condenser. The performance of the system is evaluated for different PHP diameters, working fluids, evaporator and condenser temperatures and evaporator and condenser lengths. The effect of super heating and sub cooling the refrigerant are also studied. The results showed an increase in performance of the system at higher evaporator and lower condenser temperatures. The best results are obtained with R-12 as the working fluid. Also there is an increase in the COP of the system due to decrease in pressure drop in the condenser.
Thermodynamic Analysis and Optimization of a CO2 Based Transcritical Refrigeration System with an Ejector
Authors: Ahammed Md. Ezaz , Bhattacharyya Souvik , Ramgopal Maddali
Published: July 2014

In the present paper some results obtained from the thermodynamic analysis of a CO2 based transcritical refrigeration system are presented. The system studied uses an ejector as an expansion device in place of the conventional throttle valve. Results are obtained considering constant pressure mixing process in the mixing chamber of the ejector. The compressor discharge pressure and ejector entrainment ratio are optimized for maximum COP. The required compressor displacement rate per ton of refrigeration (specific piston displacement rate, PD) is calculated at the optimum conditions. A correlation is obtained for PD in terms of the evaporator, gas cooler exit and ejector efficiencies. From the sensitivity analysis it is seen that of all the parameters, the PD is most sensitive to evaporator temperature.
Thermoeconomic Analysis of R134a-DMAC Vapour Absorption Refrigeration System
Authors: Mariappan V. , Udayakumar M. , Anwar Sah Md Fahim
Published: July 2014

This study focuses on the analysis of Tetrafluoroethane-Dimethylacetamide (R134a-DMAC) VAR system based on both thermodynamic and economic point of view and optimal operating parameter are proposed. In thermodynamic analysis mass flow rates, temperature, pressure, enthalpy, mass fraction and exergy of various state points are determined and based on the above state point properties the system COP and exergetic efficiency are calculated. Simplified cost minimization methodology is applied to evaluate the economic costs of all the internal flows and products of the system by formulating exergoeconomic cost equations. Thermoeconomic comparisons are made between this system and H2O-LiBr and NH3-H2O. It is found that thermodynamic performance of H2O-LiBr is better than NH3-H2O and R134a-DMAC systems whereas thermoeconomic performance of R134a-DMAC is better than the other two systems. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}
Design and Analysis of an Automotive Vacuum Pump
Authors: Thaslim A. Anisa , Suresh Kumar J. , Jayachandran A. , Damodaran D. , Vasudevan R.
Published: July 2014

In the present study, mathematical modelling of different chamber profile of the vacuum pump to evaluate the evacuation time is developed. The validity of the developed mathematical modelling is demonstrated by performing an experiment on the vacuum pump with elliptical profile. The performance of the elliptical profile is also compared with that of the circular profile chamber of vacuum pump. It is shown that the evacuation time of vacuum pump with an elliptical chamber is lower than with a circular profile. Various parametric studies are also performed to investigate the effect of rotor eccentricity, ratio of minor and major axes of the elliptical profiles, air tank capacity on evacuation time of the vacuum pump.
Effect of Convergent Angle on Flow Characteristics of Y-Shaped Diffusers Using CFD
Authors: Karuppa Raj R. Thundil , Dhyan Shankar M.P.
Published: July 2014

Diffusing ducts are used in fluid flow systems, mainly in aeroplane engine inlets to decelerate the flow and to correspondingly increase the static pressure. The main problem in achieving a high pressure recovery is the flow separation which results in non-uniform distribution and excessive losses. The present work is aimed to study the flow characteristics in Y-shaped diffusing ducts. The Y-shaped diffuser has rectangular inlets and the outlet is circular with a certain settling length for the flow to be stabilized. The diffuser is modeled in CATIA V5 and further discretized using ICEMCFD12.1. Hexahedral mesh is generated for all diffuser cases, which have been used to capture the hydrodynamic boundary layers. ANSYS CFX 12.1 based on finite volume technique, using k-ε turbulence model is adopted for predicting the flow. The flow field through the 3-dimensional domain is captured by solving the appropriate governing equations namely, the continuity equation and the momentum equation. The convergence criterion is set to 10E-06 for mass and momentum. The whole investigation is done in two phases: in the first phase a commercial CFD code is validated for the results obtained for an S-shaped diffuser and in the second phase the same idea is then extended for the analysis of Y-shaped diffuser. The coefficient of static pressure, cross flow and axial flow velocity distributions are calculated based on the mass averaged quantities for the Y-shaped diffusers (30o and 40o).
Effect of Deep Cryogenic Treatment on Machinability of NiTi Shape Memory Alloys in Electro Discharge Machining
Authors: Jatti Vijaykumar S. , Singh T.P.
Published: July 2014

NiTi shape memory alloys usually consist of binary alloys of nickel and titanium concentrations near the equiatomic composition. Due to high hardness of NiTi alloys, the traditional machining processes are not able to machine these alloys. Nontraditional processes like electro discharge machining (EDM) ; due to their unique mechanism of material removal are useful alternatives in such case.The overall machining performance of electro discharge machining process depends on the electrical, thermal properties of both tool and workpiece materials. Cryogenic treatment has a history of improving mechanical, electrical, and thermal properties of materials. Recently, very few researchers applied cryogenic cooling and treatment of workpiece and tool in conventional EDM and found notable improvement in machining performance. In this study, NiTi shape memory alloys was subjected to around-185C for cryogenic treatment and the effects of cryogenic treatments on the machiniability of NiTi shape memory alloys workpieces in electro discharge machining have been investigated. The electrical conductivity of workpiece exceptionally improved. Experimental results showed about 19% increase in material removal rate of cryogenic treated workpieces. Variations in tool wear rate was found to be marginal.
Crack Detection in Rotating Cantilever Beam by Continuous Wavelet Transform
Authors: Banerjee Amit , Pohit G.
Published: July 2014

This paper presents an investigation methodology for detection of size and location of open edge transverse crack on a rotating beams using continuous wavelength transform. Generally, vibration characteristic of abeam like structure changes significantly due to the presence of crack. However when the crack is relatively small, it is difficult to identify the presence of the crack from the vibration response data only. In the present case, vibration parameter, such as, mode shapes of damaged beams are obtained using the finite element method. The CWT is implemented with different scales on mode shape of the rotating beam to evaluate crack size and its location. It is also shown that this method can produce satisfactory results with some limitation based on mode shape profile. In addition to the the profile quality, other determining factors are scale and resolution of the detection signal
Hydraulic Circuit in Damper: An Overview
Authors: Paswan Ramashankar , Das Jayanta , Kumar N. , Kumar Ajit , Mishra Santosh Kumar , Sujit Kumar
Published: July 2014

A Hydraulic circuit is a group of components such as pumps, actuators, and control valves so arranged that they will perform a useful task. When analyzing or designing a hydraulic circuit, the following three important considerations must be taken into account.Safety of operation,Performance of desired function, Efficiency of operation.It is very important for the fluid power ( Hydraulics and Pneumatics ) designer to have a working knowledge of components and how they operate in a circuit. Hydraulic circuits are developed through the use of graphical symbols for all components. Keywords: damper,hydraulic circuit,
Effect of Offset Distance on Cutting Forces and Heat Generation in Multi-Tool Turning Process
Authors: Kalidasan R. , Yatin M. , Sarma D.K. , Senthilvelan S.
Published: July 2014

Productivity enhancement assumes a paramount importance in today’s competitive industrial world. The aim of this work is to improve productivity in a conventional lathe with two single point cutting tools machining a workpiece simultaneously. An additional tool holding fixture is fabricated and integrated so that distance between the two cutting tools can be varied and has a provision to provide individual depth of cut. Experiments were performed on gray cast iron workpiece at different offset distances between the cutting tools, at a particular cutting speed, feed rate and depth of cut. In the multi-tool turning process, lagging rear cutting tool experiences lesser cutting force than leading front cutting tool. This behaviour is due to the machining of front cutting tool preheat as well as reduction of effective cutting speed while machining with rear cutting tool. With increase in offset distance, moment acting on the work piece contributes to increase in resistance against machining and hence front tool experiences higher force than rear cutting tool.
Modal Analysis of a Container Filled with Water
Authors: Chandravanshi M.L. , Mukhopadhyay Alok Kumar
Published: July 2014

Modal analysis plays an important role at design stage which helps in diagnosing problems related to structural vibration. This paper delineates about the experimental work to investigate the modal parameters, such as mode shapes and natural frequencies of a metallic container. The modal parameters have been experimentally determined for the empty container, the container filled with one liter of water and the container filled with two liters of water. Theoretical analysis is also carried out through finite element analysis using ANSYS workbench 14 for finding out modal parameters of the empty container only. The boundary conditions of the container in the experimental and FEM analysis have been kept same. The values of modal parameters obtained by the two methods then compared for their proximity
Design and Fabrication of Flexible Three Link Manipulator for Pick and Place Application
Authors: Naveen S.K. , Rajesh Kumaar Devaraj , Pandian P. Pal
Published: July 2014

Flexibility plays a key role in robot based applications, where the ability to perform complex tasks in semi structured or even unstructured environments is strategic.Most industrial robot operates inside a security fence which separates them from human workers, but not all. Flexibility, lightness in relation to the mass to be displaced and energy efficiency are acquiring increasing significance in automation. We can achieve higher performance in robots by optimizing the parameters like high-speed operation, lower energy consumption, lighter weight and safer operation. In this paper a pick and place robot is designed and developed to achieve effective automation with higher safety and with greater ease. The main objectives of designing this flexible manipulator are to reduce its mass and to minimize its vibrations in the end-effector, which enhances good accuracy in positioning.This can be achieved by bringing down the number of working components and jointswhich reduce various losses. The greater mass can be transferred from one place to another place with relatively lesser mass of flexible three link manipulator. The various problems were encountered and rectified during the design and fabrication of flexible three link manipulator for pick and place application.
Development of a Contact Based Human Arm Motion Analysis System for Virtual Reality Applications
Authors: Nalam Varun , Manivannan P.V.
Published: July 2014

This paper presents the development of a system for analyzing and adapting the Human Arm motion for virtual reality applications. The proposed system consists of number of Flex sensors, Inertial Measurement Units and Embedded Data Acquisition System, to record the joint angles for deriving the kinematic states (position, velocity and acceleration) of different parts of the human arm. A flexible structure is used for holding the sensors on the human arm at the required position, without hindering the movement. The embedded circuit utilizes a 32-bit Microcontroller to process the data from various sensors and transmits digitized data to the central computer for computing the various kinematics parameters. The system has been tested against standard motion tracking device and is found to perform close to the reference device with an average error of 6% . Such a device can be used to simulate critical operations in medicine and industry and analyze performance during various tasks.