bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of an Off-Road Diesel Engine Driven With Different Animal Fat Based Biofuels
Authors: Niemi Seppo , Vauhkonen Ville , Hiltunen Erkki , Virtanen Sampo , Karhu Toomas , Ekman Krister , Salminen Heikki , Appelberg Sanna
Published: July 2010

The demand for increased use of biofuels in both on- and off-road diesel engines is growing. The carbon dioxide emissions must be reduced, but the increase in the petroleum prices and possible shortage of crude oil also promote the interest in biofuels. Simultaneously, exhaust pollutants of diesel engines have to be drastically reduced. The nitrogen oxides (NOx) and particulate matter (PM) form the main challenge for diesel exhaust cleaning. Despite the emissions reduction, the fuel economy of the engines should be kept at a sufficient level to also prevent the CO2 increase. In the present study, a turbocharged, inter-cooled direct-injection off-road diesel engine was driven with two animal fat based bio-fuels, namely steelhead (or rainbow trout) methyl ester (StME) and crude steelhead oil (StO). Crude or neat biofuels are also of interest since medium-speed engines are able to burn unrefined bio-oils. A vegetable oil based fuel, canola oil methyl ester (RME) served as the main reference biofuel. The baseline results were measured with commercial low-sulfur diesel fuel oil (DFO). The main aim of the project was to clarify how the waste-derived animal fat based biofuels are suited to engine use. The performance and emissions characteristics of the engine were determined. In addition to regulated emissions, the particle size distributions were also examined. The results showed that the studied animal fat derived ester was very suitable for the off-road test engine. NOx increased but hydrocarbons (HC), smoke, and PM mass decreased (by up to 60%) while thermal efficiency and carbon monoxide (CO) remained approximately unchanged. The particle number emissions were competitive relative to DFO. Raw fish oil StO reduced HC emissions but increased NOx and particle mass and number emissions. CO and smoke behaved ambiguously, so further investigation is needed for this fuel.
A Novel Cooling Strategy for a Diesel Engine to Improve Engine Power Efficiency and Emissions
Authors: Choi Kyung-Wook , Kim Ki-Bum , Lee Ki-Hyung
Published: July 2010

Stringent regulations on CO2 emission causing greenhouse effect have drawn attention of automotive manufacturers to the diesel engine. The trend is to increase the engine power per liter, and research are being carried out to satisfy the regulation. In this paper, a new cooling strategy was proposed to control coolant more efficiently. Before carrying out a new cooling strategy, preliminary tests on the cooling components were performed. Measurement of metal temperature of the engine indicates that the conventional cooling system was designed inappropriately large to endure at high load conditions. Therefore several strategies were adapted to optimize the size of the conventional cooling system using an Electric Water Pump (EWP), Electric Valve (EV) and low temperature EGR cooler. A cooling system in a 2.7 liter Direct Injection Diesel Engine was modified for the purpose of this study, and the strategies were tested in a stationary test bench. As a result, emission and fuel consumption decreased in high coolant temperature and low coolant flow. Warm-up period in which THC and CO emissions were significant was shortened by controlling the coolant flow paths using EVs. An essential component in a diesel engine is an Exhaust gas recirculation (EGR) system that decreases combustion temperature and oxygen concentration resulting in a substantial reduction of NOx emission. The coolant circulates through the EGR cooler so that the EGR gas temperature could be dropped down, resulting in more efficient combustion. New cooling strategies were found to improve emissions and fuel economy of engines.
Design of a Flow Reactor for Testing Multi-Brick Catalyst Systems Using Rapid Exhaust Gas Composition Switches
Authors: Klinkert Stefan , Hoard John W. , Sathasivam Sakthish R. , Assanis Dennis N. , Bohac Stanislav V.
Published: July 2010

In recent years, diesel exhaust gas aftertreatment has become a core combustion engine research subject because of both increasingly stringent emission regulations and incentives toward more fuel-efficient propulsion systems. Lean NOX traps (LNT) and selective catalytic reduction (SCR) catalysts represent two viable pathways for the challenging part of exhaust gas aftertreatment of lean burn engines: NOX abatement. It has been found that the combination of LNT and SCR catalysts can yield synergistic effects. Switches in the operation mode of the engine, temporarily enriching the mixture, are required to regenerate the LNT catalyst and produce ammonia for the SCR. This paper describes the design of a catalyst flow reactor that allows studying multi-brick catalyst systems using rapid exhaust gas composition switches and its initial validation. The flow reactor was designed primarily to study the potential of combining different aftertreatment components. It can accommodate two sample bricks at a time in two tube furnaces, which allows for independent temperature control. Moreover, the flow reactor allows for very flexible control of the composition and flow rate of the synthetic exhaust, which is blended using mass flow controllers. By using a two-branch design, very fast switches between two exhaust gas streams, as seen during the regeneration process of a LNT catalyst, are possible. The flow reactor utilizes a variety of gas analyzers, including a 5-Hz FTIR spectrometer, an emissions bench for oxygen and THC, a hydrogen mass spectrometer, and gas chromatographs for HC speciation. An in-house control program allows for data recording, flow reactor control, and highly flexible automation. Additionally, the hardware and software incorporate features to ensure safe testing. The design also has provisions for engine exhaust sampling.
Crankcase Emission Contributions to PM for Two Tier 2 Line-Haul Locomotives
Authors: Osborne Dustin T. , McDonald Joseph , Khalek Imad
Published: July 2010

This paper documents the quantification and characterization of particulate matter (PM) emitted from two Tier 2 diesel locomotives, and the impact of crankcase ventilation (CCV) on PM emissions. Emission testing was performed on one General Electric (GE) model ES44DC locomotive, and one Electro-Motive Diesel (EMD) model SD70ACe. A semi-continuous organic carbon/elemental carbon (OC/EC) analytical procedure was used to collect and determine the OC and EC of PM. PM was also measured gravimetrically using Teflon membrane filters. Testing was performed for the locomotives in an unmodified configuration “with CCV”, and then again without the CCV included in the emissions measurements. Without CCV, the two-stroke SD70ACe brake specific filter-based PM and OC/EC PM, over the Line-haul Locomotive Duty Cycle (LHLDC), were reduced by approximately 15% to 16%, respectively, compared to testing with CCV. The 4-stroke ES44DC showed a reduction of 11% for the OC/EC PM which was mainly due to a reduction in OC PM. When crankcase emissions were not included, OC PM was reduced for nearly all throttle notches, and especially under high load conditions, although the differences were not always significant at a 95% confidence interval. With CCV, the relative OC portion of the Line-haul composite PM value for both locomotives was approximately 42–47%. Without CCV, the absolute brake-specific OC PM over the LHLDC was reduced by 30%, thereby reducing the relative OC portion to approximately 34–38%. This work showed that the OC PM fraction is significant for the locomotives tested, and controlling OC can lead to more than 40 percent reduction in PM. Furthermore, almost one-third of the OC PM was contributed by CCV, therefore better control of blow-by PM from both locomotive types can lead to a significant reduction in OC PM.
NOx and Fuel Economy Challenges With EMD Two-Stroke Engines: Variable Injection and Valve Timing
Authors: Riley Michael B. , Hedrick John C.
Published: July 2010

NOx emissions are a major cause of ozone formation. Several technologies to mitigate NOx in internal combustion engines have been developed, both in-cylinder and aftertreatment. Some of these newer technologies are being implemented on new engines, but older engines, especially large diesel engines, have few options to reduce these emissions substantially. The most common method of NOx reduction is retarding the start of injection timing but this has a penalty in fuel economy. A program has been undertaken on an EMD 645E two-stroke diesel engine to combine a simple mechanical system with both retarded and variable start of injection — to mitigate NOx — with variable valve timing to offset the fuel economy penalty. Simulation modeling and on-engine experimentation have been carried out to quantify the extent of the NOx reduction with the impact on fuel economy.
Proposed Combustion Strategy for Increasing Thermal Efficiency in Open Chamber Stationary Gas Engines
Authors: Tozzi Luigi , Sotiropoulou Emmanuella , Adair Jessica , Chiera Domenico
Published: July 2010

The quest for high engine brake thermal efficiency (BTE) in medium size (140mm – 190mm bore), lean-burn gas applications becomes increasingly difficult as lower emission levels (250mg/Nm3 NOx) are targeted. A traditional approach to offsetting this negative trend has been to design the piston and the intake ports to create high turbulence and homogeneous mixtures leading to faster combustion burn rates with leaner mixtures. This paper proposes a new combustion strategy aimed at optimizing fuel-air mixture stratification in the main combustion chamber. This would result in maximum fuel concentration within a passive prechamber plug leading to high turbulence flame jet (HTFJ) penetration in the main combustion chamber and, therefore, faster combustion burn rates. Experimental correlation of a combustion model is provided for flame jet ignition in a quiescent, mildly stratified combustion chamber through three different cases. The first case uses a traditional J-gap spark plug; the second, a prechamber plug that is not optimized for the fuel distribution present in this combustion chamber. Finally, the third case makes use of a prechamber plug that has been configured to have properly oriented HTFJ. These three cases constitute the basis of the proposed combustion strategy leading to significant increase in engine brake thermal efficiency (BTE).
Effect of Long Storage Stability of Karanja (Pongamia) Derived Biodiesel Fuel on the Performance, Combustion and Emission Characteristics of a Multi-Cylinder Turbo-Charged Direct Injection Diesel Engine
Authors: Anand K. , Mehta Pramod S. , Sharma R. P.
Published: July 2010

Due to its renewable nature, emission advantage and easy adaptation, biodiesel is emerging as an alternative to fossil diesel. There are however concerns on biodiesel storage stability aspect due to the presence of unsaturated content in its composition. This paper discusses on studying the effect of long term storage stability of Karanja derived biodiesel (KME) on the performance, combustion and emission characteristics of a turbo-charged, multicylinder, direct injection diesel engine. For aged karanja derived biodiesel (A-KME) stored in a mild steel container for 500 days, both the fuel properties and the engine performance are found to change. It is observed that the aged fuel as compared to the fresh karanja derived biodiesel (F-KME) showed i) an increase in the acid value and kinematic viscosity from 0.374 mg KOH/g to 0.89 mg KOH/g and 5.6 to 5.7 cSt respectively, ii) a slight decrease in ignition delay and maximum rate of pressure rise, iii) a maximum increase in peak cylinder pressure of about 10% and duration of combustion of 8 deg. CA, iv) a decrease in brake thermal efficiency to an extent of over 4%, v) an increase in un burnt hydrocarbon emissions particularly at low loads, and, vi) a significant increase in exhaust nitric oxide (∼30%) and the smoke emissions (∼78%) at higher loads.
A Study on the Applicability of Straight Vegetable Oils to Medium Speed Diesel Engines
Authors: Park Hyoung-Keun , Ghal Sang-Hak , Park Tae-Hyung , Ahn Yong-Hee , Kim Sung-Hyeok
Published: July 2010

Straight vegetable oil (SVO) fuels such as palm oil, animal fat oil and waste vegetable oil were tested as fuels in a single-cylinder diesel engine to evaluate applicability to medium-speed diesel engines. Fuel-related properties of the SVO were assessed and compared with conventional marine diesel fuel oil (MDO). The total acid number (TAN) of the SVO fuels changed during a short interval in a drying oven which heated the SVO fuels to 170 degrees Celsius for several weeks. The SVO have not gone rancid any further after reaching limit. And the TAN of the SVO fuels was not related to corrosion of the parts. The SVO fuels needed to be heated to an appropriate temperature to use as fuel of the engine since the SVO fuels are more viscous than conventional diesel fuels. Both the injection period and the injection pressure increased due to low heating values of the SVO fuels. By the same token, fuel oil consumption increased over 10%. The overall exhaust emissions were lower with the SVO fuels, but NOx emission was as much as MDO at the higher loads.
Improvements in Efficiency and Mixture Formation for an Innovative Diesel HCCI Concept
Authors: Musu E. , Rossi R. , Gentili R.
Published: July 2010

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in dilute homogeneous mixtures. The combustion rate must be reduced by suitable solutions such as high rates of Exhaust Gas Recirculation (EGR) and/or lean mixtures. HCCI is considered to be a very effective way to reduce engine pollutant emissions, however only a few production engines have been built. HCCI combustion currently cannot be extended to the whole engine operating range, especially to high loads, since the use of EGR displaces air from the cylinder, limiting engine mean effective pressure, thus the engine must be able to operate also in conventional mode. This paper concerns a study of an innovative concept to control HCCI combustion in diesel-fueled engines. The concept consists in forming a pre-compressed homogeneous charge outside the cylinder and in gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the transfer flow rate, and high pressure rise rates, typical of standard HCCI combustion, can be avoided. This new combustion concept has been called Homogenous Charge Progressive Combustion (HCPC). This paper concerns CFD analysis focused on improving efficiency and reducing pollutant emissions considering a new HCPC engine configuration. Results show an indicated efficiency around 45% and a consistent reduction of soot emission compared to conventional diesel engine.
Simulation of Instantaneous Heat Transfer in Spark Ignition Internal Combustion Engines: Unsteady Thermal Boundary Layer Modelling
Authors: Buttsworth David R. , Agrira Abdalla , Malpress Ray , Yusaf Talal
Published: July 2010

Simulation of internal combustion engine heat transfer using low-dimensional thermodynamic modelling often relies on quasi-steady heat transfer correlations. However, unsteady thermal boundary layer modelling could make a useful contribution because of the inherent unsteadiness of the internal combustion engine environment. Previous formulations of the unsteady energy equations for internal combustion engine thermal boundary layer modelling appear to imply that it is necessary to adopt the restrictive assumption that isentropic processes occur in the gas external to the thermal boundary layer. Such restrictions are not required and we have investigated if unsteady modelling can improve the simulation of crank-resolved heat transfer. A modest degree of success is reported for the present modelling which relies on a constant effective turbulent thermal conductivity. Improvement in the unsteady thermal boundary layer simulations is expected in future when the temporal and spatial variation in effective turbulent conductivity is correctly modelled.
The Effects of Diesel Injector Needle Motion on Spray Structure
Authors: Powell C. F. , Kastengren A. L. , Liu Z. , Fezzaa K.
Published: July 2010

The internal structure of diesel fuel injectors is known to have a significant impact on the steady-state fuel distribution within the spray. However, little experimental or computational work has been performed on the dynamics of fuel injectors. Recent studies have shown that it is possible to measure the three-dimensional geometry of the injector nozzle, and to track changes in that geometry as the needle opens and closes in real time. This has enabled the dynamics of the injector to be compared with the dynamics of the spray, and allows CFD simulations to use realistic time-dependent flow passage geometries. In this study, x-ray phase-enhanced imaging has been used to perform time-resolved imaging of the needle seat area in several common-rail diesel injection nozzles. The fuel distributions of the sprays emitted by these injectors were also studied with fast x-ray radiography. Correlations between eccentric motions of the injector needle valve and oscillations in the fuel density as it emerges from the nozzle are examined. CFD modeling is used to interpret the effect of needle motion on fuel flow.
Improved Eulerian-Lagrangian Spray Simulation by Using an Enhanced Momentum Coupling Model
Authors: Kim Sayop , Park Sung Wook , Lee Chang Sik
Published: July 2010

This study describes a strategy for reducing grid-size dependency that mainly comes from inaccurate calculation of the droplet-gas interactions and droplet collision modeling. The present paper suggests an enhanced momentum coupling (EMC) model and introduces the improved collision models to obtain the goal of reducing grid dependency. For conventional CFD codes, due to the low computational cost and effort, the Eulerian-Lagrangian method is preferred in simulating the multiphase flow, for instance, liquid spray penetrating into gaseous phase. However, it is well known that the spray computations are highly dependent on the grid resolution because momentum gain from liquid droplet less or more transferred to unit gaseous mass according to the grid cell volume, resulting in inaccurate prediction of droplet-gas relative velocity. For this reason, the grid-size dependency leads to inaccurate prediction of spray tip penetration and mean droplet size. To overcome the problem, in the present study, enhanced sub-models for reducing the grid dependency are introduced and implemented in the three dimensional engine simulation code, KIVA-3V. In the EMC model, keeping the standard Eulerian-Lagrangian method, the momentum coupling term in the momentum conservation equation of the Eulerian phase is revised and lack of momentum transfer due to inadequate cell resolution is compensated regarding the gaseous volume receiving the effective spray momentum. Computations were conducted using the EMC model, the gas-velocity interpolation scheme, and grid-size independent collision model under the high-pressure diesel injection conditions. From the results, the improved model composed of the EMC model and the grid independent collision model give a dramatic decrease in grid dependency of spray tip penetration and overall droplet size.
High Cycle Fatigue Life Assessment of a Heavy Duty Diesel Engine Cylinder Head
Authors: Chamani Hamidreza , Malakizadi Amir
Published: July 2010

Among all critical components in heavy duty diesel engines, cylinder head is generally counted as the most challenging part due to the complex loading conditions. This component experiences both thermal and mechanical stresses. Temperature difference between combustion gases and cooling water induces significant thermal stress in the flameface, while the firing pressure builds up cyclic mechanical stresses superimposed on the former thermal stress. On the other hands, cylinder heads are geometrically complex and generally contain many small fillets and blends. These small geometrical features and complex loading condition cause multiaxial stress state which should be considered during High Cycle Fatigue (HCF) life assessment. In this study, a detailed finite element analysis has been conducted on a heavy duty diesel engine cylinder head, which is followed by HCF life assessment. In order to predict the HCF safety factor, a post-processing routine has been developed using ANSYS Parametric Design Language (APDL) based on a normal stress critical plane approach. This method is shown as a promising approach for multiaxial HCF life assessment of a wide range of engineering metals. Moreover, normal stress critical plane approach is known as a computationally time efficient approach for the huge finite element models. Notch effect has been considered by introducing the relative stress gradient parameter, which is obtained from the best fit of fatigue test data for different notch geometries. Finally, the effect of HCF on Low Cycle Fatigue (LCF) crack growth has been discussed.
Injector Coking Effects on Engine Performance and Emissions
Authors: Arpaia Antonio , Catania Andrea E. , d’Ambrosio Stefano , Ferrari Alessandro , Luisi Sabino P. , Spessa Ezio
Published: July 2010

The physical origin of injector coking in diesel engines was clarified and the most critical design parameters and operating variables for the occurrence of the phenomenon were identified. Injector fouling was shown to be affected by many factors, such as injector temperature, nozzle configuration, hole diameter and conicity, fuel composition. In particular, minute quantities of Zn, which can be added to the fuel, were verified to sensibly catalyze the growth of the undesired deposits. Optical and Scanning Electron Microscope (SEM) analyses were conducted both outside and inside different injectors and four locations were identified as main sites for the deposits. Furthermore, different typologies of coking, such as dry and wet coking, were identified and discussed. Energy Dispersive X-ray (EDX) spectroscopy images of the deposits on the spray hole walls revealed a significant presence of Zn when the fuel was doped with such an element. An extensive campaign of experimental tests was carried out at the engine test bed with different nozzle setups in order to evaluate performance deteriorations, in terms of power output, fuel consumption and emissions, after distinct ageing processes. The effects of both Zn concentration in the fuel and ageing time on the losses of engine performance were separately essessed. A previously developed combustion multi-zone diagnostic model was applied to prove the consistency between experimental in-cylinder pressure time hystories and engine-out emissions. Finally injection rate time histories were measured at the hydraulic test rig under different working conditions for both new and aged injectors. The experimental changes in the EVI profiles subsequent to fouling were analyzed and related to the corresponding variations in emissions and engine power, which resulted at the engine test bench.
Effects of B20 on Emissions and the Performance of a Diesel Particulate Filter in a Light-Duty Diesel Engine
Authors: Peterson Amy M. , Lee Po-I , Lai Ming-Chia , Wu Ming-Cheng , DiMaggio Craig L. , Ng Simon , Tang Haiying
Published: July 2010

This paper compares 20% bio-diesel (B20-choice white grease) fuel with baseline ultra low sulfur diesel (ULSD) fuel on the emissions and performance of a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) coupled to a light-duty 4-cylinder 2.8-liter common-rail DI diesel engine. The present paper focuses on the comparison of the fuel effects on loading and active regeneration of the DPF between B20 and ULSD. B20, in general, produces less soot and has lower regeneration temperature compared to soot loaded with ULSD. NO2 concentrations before the DPF were found to be 6% higher with B20, indicating more availability of NO2 to oxidize the soot. Exhaust speciation of the NO2 availability indicates that the slight increase in NOx from B20 is not the dominant cause for the lower temperature regeneration and faster regeneration rate but the reactivity of the soot that is in the DPF. Formaldehyde concentrations are found to be higher with B20 during regeneration due to increased oxygen concentrations in the exhaust stream. Finally the oil dilution effect due to post injection to actively regenerate the DPF is also investigated using a prototype oil sensor and FTIR instrumentation. Utilizing an active regeneration strategy accentuates the possibility of fuel oil dilution of the engine oil. The onboard viscosity oil sensor used was in good agreement with the viscosity bench test and FTIR analysis and provided oil viscosity measurement over the course of the project. Operation with B20 shows significant fuel dilution and needs to be monitored to prevent engine deterioration.
Design of Measurement and Detection Devices of Curvature Through the Synergic Integral Operators of the Mechanics on Light Waves
Authors: Bulnes Aguirre Francisco , Herna´ndez Alvarez Eduardo , Maya Castellanos M. C. Juan Carlos
Published: July 2010

Of a theory of integrals for the determination of observables of fields and particles in mathematics and mechanics [1–3], and applying a generalization of the principle from the minimum action to an entire field of objects to obtain a combined action of all the useful movement trajectories in the evaluation of an observable through synergic integral operators, [1, 4], it is designed and it develops an electromagnetic device to measure the curvature of objects using the values of these integrals on geodesic and movement trajectories generated by the field and the deviations of the waves generated by the device. The most concrete case is the obtaining of a device that measures the curvature through waves of light and its reflections with tomography on the surfaces of bodies. As future addresses of this investigation it is wanted to use this device to measure curvature and torsion of the universe, as well as to detect fields, particles and regions of the susceptible space-time for the interstellar trips.
The Measurement of Overall Elastic Stiffness and Bulk Modulus in Anisotropic Materials: Semiconductors
Authors: Gaith Mohamed S. , Alhayek I.
Published: July 2010

In this study, the correlation between macroscopic and microscopic properties of the II-IV semiconductor compounds ZnX (X = S, Se, Te) is investigated. Based on constructing orthonormal tensor basis elements using the form-invariant expressions, the elastic stiffness for cubic system materials is decomposed into two parts; isotropic (two terms) and anisotropic parts. A scale for measuring the overall elastic stiffness of these compounds is introduced and its correlation with the calculated bulk modulus and lattice constants is analyzed. The overall elastic stiffness is calculated and found to be directly proportional to bulk modulus and inversely proportional to lattice constants. A scale quantitative comparison of the contribution of the anisotropy to the elastic stiffness and to measure the degree of anisotropy in an anisotropic material is proposed using the Norm Ratio Criteria (NRC). It is found that ZnS is the nearest to isotropy (or least anisotropic) while ZnTe is the least isotropic (or nearest to anisotropic) among these compounds. The norm and norm ratios are found to be very useful for selecting suitable materials for electro-optic devices, transducers, modulators, acousto-optic devices.
Conceptual Design and Kinematic Analysis of a Compliant Parallel Mechanism for Micro/Nano Scale Manipulation
Authors: Zhang Dan , Li Beizhi , Yang Jianguo , Gao Zhen
Published: July 2010

There is a great need in various fields to be able to produce motion on a micro/nano scale with three translational degrees of freedom (DOF). Such fields include optical alignment, cell injection operation, precision manufacturing and micro electro mechanical systems. This research is concerned with the design and analysis of a compliant parallel micromanipulator (CPM) for micro/nano scale manipulation. Several kinematic structures including a novel three-cylindrical-prismatic-revolute CPM is proposed. Based on the established pseudo-rigid-body model of the CPM, the kinematic models are derived. The CPM is featured by pizeo-driven and flexure hinges, thus it has advantages such as sub nanometer resolution, large force generation, sub-millisecond response, and extremely low steady state power consumption.
Efficient Aerodynamic Optimization of an Impulse Turbine Rotor Cascade
Authors: Benini Ernesto , Ponza Rita , Comis da Ronco Claudio , Ventrucci Irene
Published: July 2010

This paper describes an efficient aerodynamic optimization method for an impulse turbine rotor cascade. The aim of the optimization is to minimize the total pressure losses through the cascade by controlling the shape of a portion of the turbine airfoil, i.e. the pressure side and the rear part of the suction side. This is done with the intention of reducing the complexity of the problem to be solved, as well as because of the particular nature of the losses being generated. For this purpose, the commercial Computational Fluid Dynamics (CFD) code Fluent© is used where a transition model is implemented, prior an accurate validation has been carried out. A proper optimization procedure is developed which is based on a sequential use of several modules: first, a Design of Experiment (DOE) analysis is performed, then a Response Surface Methodology (RSM) is employed to build a surrogate model of the fitness function, which is in turn minimized using a Sequential Quadratic Programming (SQP) algorithm. The benefits of this approach are demonstrated, in that the total pressure coefficient of the cascade can be lowered up to 13%.
Design and Testing of Low-Speed Wind Turbine Blade
Authors: Amano R. S. , Malloy R. J.
Published: July 2010

There is a need for clean, cheap, and efficient energy. One potential candidate for a source of this energy is a wind energy. In order to maximize the amount of energy captured, a new, low airspeed wind turbines must be designed. A wind turbine was created using the NACA 4412 foil shape and a decreasing chord length with increasing distance from the center of the turbine. The angle of attack was also varied. The airfoil was analyzed in CFD and tested via wind tunnel model. The turbine was connected to a motor which was connected to a resistor and current and voltage meters. Using the voltage and current data at a prescribed rate of rotation, the power generated was calculated. Despite the shortcomings of the model, decent power output was generated. Since the wind tunnel could only perform up to 5 ft/s (or 3.4 mph), this shows that the turbine is acceptable for low wind speeds. For practical use the turbine would need to be scaled to a greater size and a PID controller that can generate higher resistance would need to be employed.
A Robust Anti-Swing Trajectory Control of Overhead Cranes With High-Speed Load Hoisting: Simulation Study
Authors: Lee Ho-Hoon
Published: July 2010

This paper proposes a new approach for the anti-swing trajectory control of overhead cranes that allows simultaneous high-speed load hoisting. The objective of this study is to design an anti-swing trajectory control scheme that is robust to unavoidable mechanical inaccuracies and installation errors such as locally sloped trolley rails. First, a coupled sliding surface is defined based on the load-swing dynamics, and then the stability of the coupled sliding surface is shown to be equivalent to that of trolley tracking errors. Next, a robust anti-swing trajectory control scheme, minimizing the coupled sliding surface asymptotically to zero, is designed based on the trolley and load-hoisting dynamics. Finally, the proposed control is extended to an adaptive scheme. In this study, the Lyapunov stability theorem is used as a mathematical design tool. The proposed control guarantees asymptotic stability of the anti-swing trajectory control while keeping all internal signals bounded. The proposed control provides a practical solution for the robustness problem caused by the usual mechanical inaccuracies and installation errors in application. The proposed control also provides clear gain-tuning criteria for easy application. The validity of the theoretical results is shown by computer simulation.
Developing a Methodology Towards Sustainable PCD Compact Core Drilling on Planet Mars
Authors: Hamade R. F. , Manthri S. P. , Pusavec F. , Zacny K. A. , Taylor L. A. , Dillon O. W. , Rouch K. , Jawahir I. S.
Published: July 2010

This paper describes a study of core drilling into basalt rock in anticipation of a Mars mission. Since the objective is to maintain a sustainable drilling mission on this distant planet, we perform a methodical study to examine parameters which influence sustainability including PCD tool-wear and drilling forces.
Inverse Heat Conduction in a Composite Slab With Pyrolysis Effect and Temperature-Dependent Thermophysical Properties
Authors: Zhou Jianhua , Zhang Yuwen , Chen J. K. , Feng Z. C.
Published: July 2010

The inverse heat conduction problem (IHCP) in a one-dimensional composite slab with rate-dependent pyrolysis chemical reaction and outgassing flow effects is investigated using the conjugate gradient method (CGM). The thermal properties of the composites are considered to be temperature-dependent, which makes the IHCP a nonlinear problem. The inverse problem is formulated in such a way that the front-surface heat flux is chosen as the unknown function to be recovered, and the front-surface temperature is computed as a by-product of the IHCP algorithm, which uses back-surface temperature and heat flux measurements. The proposed IHCP formulation is then applied to solve the IHCP in an organic composite slab whose front surface is subjected to high intensity periodic laser heating. It is shown that an extra temperature sensor located at an interior position is necessary since the organic composites usually possess a very low thermal conductivity. It is also found that the frequency of the periodic laser heating flux plays a dominant role in the inverse solution accuracy. In addition, the robustness of the proposed algorithm is demonstrated by its capability in handling the case of thermophysical properties with random errors.
Incorporating Practical Laboratory Experiments to Reinforce Dynamic Systems and Control Concepts
Authors: Baglione Melody L.
Published: July 2010

The Cooper Union is developing a new simultaneous lecture and laboratory approach to address the pedagogical challenge of finding the appropriate balance between theory and hands-on experimentation in teaching dynamic systems and control concepts. The new approach dedicates one hour each week to laboratory experiments with the class subdivided into small student groups having greater faculty interaction. Bench top experiments from National Instruments and Quanser include DC motor and inverted pendulum modeling and control workstations. Process control test rigs from Feedback Inc. include level, flow, temperature, and pressure control trainers. Devoting significant time to laboratory experiments gives students the opportunities to fully appreciate feedback control concepts and to acquire valuable practical skills. This paper discusses the new instructional approach, preliminary results, lessons learned, and future plans for improving the systems and control curriculum.
Applications of Smart Materials in Structural Health Monitoring
Authors: Shih Hui-Ru , Zheng Wei , Walters Wilbur L.
Published: July 2010

Structural Health Monitoring (SHM) is an emerging technology devoted to monitoring and assessing of structural health. SHM emerged from the wide field of smart structures and laterally encompasses disciplines such as structural dynamics, materials and structures, non-destructive testing, sensors and actuators, data acquisition, signal processing and possibly much more. To stimulate students’ desire for pursing advanced technologies and prepare them well for their future careers, engineering and technology educators need to dedicate their efforts to educate the students with this emerging technology. At Jackson State University (JSU), three course modules (Smart Materials and Structures, Signals & Data Acquisition Systems, and Lamb Waves Generation & Detection) have been added to the existing courses to help undergraduate students develop hands-on experience for understanding this technology. The course modules do not assume prior knowledge of software and hardware, and they all follow an applied, hands-on approach. These three course modules allow students to gain insight into the SHM as well as to become knowledgeable users of the instrumentation.
Impact of Thermal Aging on the Growth of Cu-Sn Intermetallic Compounds in Pb-Free Solder Joints in 2512 Resistors
Authors: Chauhan Preeti , Osterman Michael , Pecht Michael
Published: July 2010

Interfacial intermetallic compounds (IMCs) in solder joints are formed during soldering and continue to grow after assembly. Excessive interfacial IMC growth may impact the reliability of solder interconnections due to changes in material behavior. The impact of thermal aging on IMC growth can be determined by subjecting assemblies to elevated temperatures and determining the interfacial IMC growth. This paper discusses the interfacial IMCs formed in the solder-Cu interface for SAC305, SAC105, and Sn-0.7Cu-0.05Ni+Ge (SN100C) assemblies. Test assemblies were produced using tin-finished 2512 resistors soldered onto OSP-finished copper lands. The assemblies were subjected to aging conditions of 100°C for 24 h and 600 h; and 150°C for 24 h and the impact of high temperature aging on the thickness of IMCs formed at solder-Cu interface was studied. Samples stored at room temperature for 600 h were the reference specimen for the experiment. The IMC growth observed in the lead-free solders was compared with that in eutectic SnPb. Interfacial IMCs formed in room temperature conditioned specimens were scallop shaped and non-uniform. The IMC structure evolved with aging temperature and duration resulting in smoother and more uniform IMCs in 100°C/600 h aged samples. A comparison of IMC thickness in the solders at given aging conditions revealed that SAC305 exhibited highest IMC thickness, followed by SAC105 and SN100C. SnPb showed the least IMC thickness at all aging conditions except at 150°C for 24 h. At this condition, SnPb showed IMC thickness comparable to SAC305 solder and was higher than other solders.
Mechanical Engineering Tools: A Problem-Based, Introductory Design Course at the American University of Beirut
Authors: Hamade R. F. , Ghaddar N.
Published: July 2010

Given the prevailing trend of ever decreasing number of required credits, this course solves one of the thorny issues which engineering departments encounter while developing curricula: to teach or not to teach ‘tools’. Those ‘tools of the trade’ include some truly ‘enabling technologies’ comprised of such ‘soft tools’ as CAD/CAM, MATLAB, project planning, controls and of ‘hard tools’ such as reverse engineering, assembly, machine shop fabrication processes, and printed circuit board technology. This course, ME Tools, was introduced in order to offer a viable platform which helps introduce the freshman mechanical engineering student to some of these ‘tools’ in a problem-based context. This goal is met via course organization and prevailing practices conducive to ‘active learning’ via activities and structure typically associated with collaborative and cooperative learning methods. ME Tools climaxes in a 5-event contest during which custom electric microcars are put to action in what is known around the American University of Beirut (AUB) campus as the ‘Gee Whiz contest’. Furthermore, and since the course activities revolve around one central theme, designing and racing an electric microcar, the true integral nature of this course is authenticated and revealed via this problem-based learning approach. This is accomplished as a team effort where teamwork experience and communication skills are highly stressed and practiced. The teams are organized so that the student team members are assigned to one of four functions: manager, systems engineer, analyst, and detail designer. The manner by which the students are assigned to one of these functions is done based on the students’ responses to a short (20 questions) questionnaire designed for this purpose. Assessment wise, grading of certain course grade components is mapped to the specific learning outcomes based on the cooperative, collaborative, and problem-based learning methods.
Dependence of the Equation of State in Surface Tension Prediction by the Theory of Capillarity
Authors: Wemhoff Aaron P.
Published: July 2010

The theory of capillarity was originally developed by J. D. van der Waals to provide a means of predicting interfacial (surface) tension data using saturation pressure and liquid-vapor density data. This theory was recently extended to the Redlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson fluid models. The latter two equations of state are more advanced than the Redlich-Kwong model in that they use an acentric factor to predict saturated vapor pressure values more in agreement with experimental data. However, the agreement in the predicted interfacial tension values is worse for the latter two models compared to the Redlich-Kwong model. This study features a sensitivity analysis to show that the predicted interfacial tension values are more sensitive to vapor density than liquid density and vapor pressure, and that increasing the vapor density reduces the corresponding predicted interfacial tension value. Furthermore, all three fluid models tend to overpredict interfacial tension when experimental data are applied in their predictive equations. This study finds that the reason why the simpler Redlich-Kwong model predicts better interfacial tension values than the two advanced models is because the former overpredicts vapor density moreso than the two advanced cubic fluid models, and this in turn reduces the prediction of interfacial tension to make its value more comparable to experimental data.
Analysis of Flow Instabilities in Two-Phase Natural Circulation
Authors: Wu Geping
Published: July 2010

Safety concerns of nuclear reactors have attracted the attention of researchers on flow instabilities in natural circulation boiling loops. In this theoretical study, a drift flux model which solves the conservation equations of mass, momentum and energy applicable to boiling two-phase natural circulation systems is adopted. The influence of two-phase flow parameters such as drift velocity and void distribution parameter on the loop flow rate is weak. The model is used to analysis the effects of heat flux and inlet subcooling on steady circulation flow rate. High circulation flow rate is accompanied by high heat flux and low inlet subcooling. According to the region and number of meeting points which connects the resistance pressure drop curve and the driving pressure drop curve, flow excursion and density-wave instability sometimes may occur. Further, investigations are carried out to study the effect of heat flux and system pressure on the instabilities region in natural circulation.
Experimental Research on the Similarity of Annular Flow Models and Correlations for the Condensation of R134a at High Mass Flux Inside Vertical and Horizontal Tubes
Authors: Dalkilic Ahmet Selim , Laohalertdecha Suriyan , Wongwises Somchai
Published: July 2010

This paper presents an experimental investigation on the usage of annular flow models and correlations valid especially for horizontal tubes to the downward annular flow in the vertical test section. Condensation experiments are performed at the mass flux of 340 kg m−2s−1 during co-current downward condensation of R134a in a vertical smooth copper tube having inner diameter of 8.1 mm and a length of 500 mm. The saturation temperatures are between 40–50°C, heat fluxes are between 12.8 and 45.36 kW m−2, average qualities are ranging between 0.76–0.95. The experimental apparatus are designed to capable of changing the different operating parameters such as mass flow rate, condensation temperature of refrigerant, cooling water temperature and mass flow rate of cooling water etc and investigate their effect on heat transfer coefficients and pressure drops. Considering Chen et al.’s annular flow theory on the heat transfer coefficients that are independent from tube orientation as long as annular flow exists along the tube length, the average predicted condensation heat transfer coefficient of the refrigerant is determined by means of the annular flow model of Kosky and Staub, and Von Karman universal velocity distribution correlations using interfacial shear stress proposed for horizontal and vertical tubes separately. Some well-known annular flow correlations generally used for horizontal tubes in the literature were compared with experimental condensation heat transfer coefficient obtained from vertical tube data during annular flow conditions in the test section.
Heat Transfer Analysis for Nuclear Waste Solidification Container
Authors: Lee Si Y.
Published: July 2010

The Nuclear Nonproliferation Programs Design Authority is in the design stage of the Waste Solidification Building (WSB) for the treatment and solidification of the radioactive liquid waste streams generated by the Pit Disassembly and Conversion Facility (PDCF) and Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). The waste streams will be mixed with a cementitious dry mix in a 55-gallon waste container. Savannah River National Laboratory (SRNL) has been performing the testing and evaluations to support technical decisions for the WSB. Engineering Modeling & Simulation Group was requested to evaluate the thermal performance of the 55-gallon drum containing hydration heat source associated with the current baseline cement waste form. A transient axi-symmetric heat transfer model for the drum partially filled with waste form cement has been developed and heat transfer calculations performed for the baseline design configurations. For this case, 65 percent of the drum volume was assumed to be filled with the waste form, which has transient hydration heat source, as one of the baseline conditions. A series of modeling calculations has been performed using a computational heat transfer approach. The baseline modeling results show that the time to reach the maximum temperature of the 65 percent filled drum is about 32 hours when a 43°C initial cement temperature is assumed to be cooled by natural convection with 27°C external air. In addition, the results computed by the present model were compared with analytical solutions. The modeling results will be benchmarked against the prototypic test results. The verified model will be used for the evaluation of the thermal performance for the WSB drum. Detailed results and the cases considered in the calculations will be discussed here.