bluuebunny/crossref_metadata_2025_split huggingface dataset:
CFD Analysis of a Fluidized Bed Combustor Based on Co-Firing
Authors: Kumar Hemant , Mohapatra S. K. , Singh Ravi Inder 
Published: March 2016

In this paper computational analysis of a real plant Bubbling Fluidized Bed (BFB) combustor has been done, using FLUENT 6.3, CFD code. Keeping in mind the biomass potential in the agricultural state like Punjab, India, various corporate sectors initiated the use of these renewable energy sources such as rice husk, paddy rejects and sugarcane baggase etc. in sharing with conventional fuels such as coal. The study has been done at Captive Power Plant (CPP) of Ambuja Cement Limited, Ropar, Punjab, India. The boiler, with 45TPH capacity, based on Fluidized Bed Combustion (FBC) system uses coal and biomass (70% coal and 30% biomass) as fuels.
Standard k–ε two-phase turbulence model has been used to describe the gas–solids flow in the BFB. The analysis of combustion is done by Non-Pre Mixed (NPM) approach in species model. In this paper temperature contours inside the furnace and mass fractions of O2 and CO2 have been obtained by CFD tool. Temperature in the vicinity of the bed was found up to 927 °C and at the exit of the furnace was found around 867 °C. The O2 concentration was found higher over the bed however the CO2 concentration was found more near biomass flame due to instantaneous combustion.
A Novel Magnetorheological Concentric Spiral-Flow Damper
Authors: Chang Kai Hsiang , Tong Jing Long , Chia Chou Min , Huang Kuang Yuh 
Published: March 2016

In this article, a novel design of MR damper, concentric spiral flow MR damper, is proposed. It could improve the heat dissipation problem which is usually found in traditional MR damper. The proposed MR damper has a concentric spiral flow channel around the cylinder which not only separates coils from MR fluid, but also increases the length of flow channel in a fixed space.
Experimental studies has been conducted to demonstrate the performance of the proposed MR damper, the result shows the MR damper generates the maximum damping force of 188 N without applying magnetic field and 1251 N when inputting 1.5 A at low frequency, which means the damper has high range of adjustable damping force. The CSF-damper can be used to systems or structures with low dynamic response.
Numerical and Experimental Study of Turbulent Flows Around Clark Y-14 Aerofoil
Authors: Vadake Kshitij , Cui Jie 
Published: March 2016

Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) have been instrumental in Fluid Mechanics to help solve scientific and engineering problems. This research attempts to use both techniques to perform a parametric study of turbulence flow around airfoil ClarkY-14 at various velocity and angle of attack (AoA).
Clark Y-14 airfoil was designed in the 1920’s. It demonstrated good overall performance at low and moderate Reynolds numbers. With the progress in the aviation field, its performance was sub-optimal for newer aircraft designs. However, with the advent of RC airplanes and model aircrafts, there is a renewed interest in this airfoil. Various research projects have been conducted using this airfoil, but there hasn’t been a combined EFD and CFD study of the performance characteristics of the airfoil itself, which still finds real world applications today. One important aspect of this research included the investigation of the effects of a Force Measurement Device/Sensor, which is typically used in scaled/full-size wind tunnels to mount the test model as well as measure the forces/moments acting on it during the testing. The presence of such a device could affect the quality of the data obtained from the wind tunnel testing when compared to a real world application scenario where the aforementioned device may not be present. To the best of the author’s knowledge, no detailed study has been published on the effects of such devices.
In this study, the results with and without the measuring device were generated by using CFD simulations. The results were then compared to see to what extent the inclusion of these devices will affect the results. The methodology used for this research was experimental as well as computational. In the present research, a commercially available CFD software STAR-CCM+ was employed to simulate the flows around airfoil Clark Y-14. The experimental data was obtained from wind tunnel tests using AEROLAB Educational Wind Tunnel (EWT) and compared with the simulation data from the CFD. The two data sets were in good agreement. Both experimental and simulation results were used to understand the effects of the measurement device/sensor used in the scaled wind tunnel on the lift and drag coefficients of the airfoil.
Two separate CFD simulation setups were designed to model the presence and absence of the measurement device/sensor. These setups replicated the wind tunnel setup. The airfoil was tested and simulated at different speeds as well as different AoA. The comparative study gave a useful insight on the accuracy of the CFD simulations in relation to the actual testing. The analysis of results concluded that the force measurement device/sensor had insignificant effects on the accuracy and quality of data collected through wind tunnel testing.
Development of New Backwashing Air Amplifying Device for Bag Filter
Authors: Ebisuzaki Ryo , Mukai Eijiro , Nakazato Youichi , Jitsukawa Masaru , Monden Kenji 
Published: March 2016

Bag filters are used to prevent dust exposure in many environments. They require maintenance to retain their filtration efficiency. The typical maintenance approach is pulse jet backwashing, but this method is not entirely effective for maintaining filters in all environments as its reverse air pressure is insufficient for some applications. Hence, there has been a recognized need to amplify the backwashing air.
A new type of device was recently developed on the basis of the Coandă effect, which amplifies the backwashing air and results in greater efficiency. However, it still does not offer sufficient performance (particularly when multiple devices are connected, as happens under actual use conditions), and its actuating mechanism is unclear. In this study, we investigated fluid behavior in the device and attempted to improve its design using computation fluid dynamics (CFD). We found that the Coandă effect injector does indeed improve efficiency by inducing more outer air into the device and forming a negative pressure area via overexpansion of sonic flow. We also developed an improved device that has 1.2 times higher reverse air cleaning efficiency. Our improved device improves the nozzle angle and the wall shape of the device to smoothen the supersonic flow attachment to the wall.
The CFD analysis further established that tapering to a square pipe is effective for providing a uniform supply of compressed air to multiple connected amplifying devices. In addition, this shape shortens the time to onset of amplification, and compressed air can be more effectively used. These effects were experimentally confirmed.
MEMS Wind Speed Sensor: Large Deflection of Curved Micro-Cantilever Beam Under Uniform Horizontal Force
Authors: Changizi M. Amin , Abolfathi Ali , Stiharu Ion 
Published: March 2016

Micro-cantilever beams are currently employed as sensor in various fields. Of main applications, is using such beams in wind speed sensors. For this purpose, curved out of plane micro-cantilever beams are used. Uniform pressure on such beams causes a large deflection of beam. General mechanics of material theory deals with small deflection and thus cannot be used for explaining this deflection. Although there are a body of works on analysing of large deflection [1], nonlinear deflection, of curved beams [2], yet there is no research on large deflection of curved beam under horizontal uniform distributed force.
Theoretically, the wind force is applying horizontally on curved micro-cantilever beam. Here, we neglect the effect of moving weather from beam sides.
We first aim how to drive the governed equation. A curved beam does not have a calculable centroid. Also large deflection of beam changes its curvature which would change the centroid of beam consciously. The variation of centroid makes very though calculating the bending moment of each cross section in the beam. To address this issue, an integral equation will be used. The total force will be considered as a single force applied at the centroid.
The second challenge is solving the governed nonlinear ordinary differential equation (ODE). Although there are several methods to solve analytically nonlinear ODE, Lie symmetry method, with all its complication, is a general method for this kind of equations. This approach covers all current methods in analytical solving nonlinear ODEs. In this method, an infinitesimal transformation should be calculated. All transformations under one parameter creates a group that called Lie group. A value of parameter which transfers the equation onto itself is called invariant of ODE. One can calculate canonical coordinates ODEs by the invariant. Solving the canonical coordinates ODEs yields to calculating the canonical coordinates. Canonical coordinate are used to reduce the order of nonlinear ODE [3]. By repeating this method one can solve high order ODEs.
Our last question is how to do numerical solution of ODE. The possible answer will help to explain the phenomena of deflection clearly and compare the analytical solution with numerical results. Small dimensions of beam, small values of applied force from one side and Young modules value from the other side, will create a stiff ODE. Authors experience in this area shows that the best method to sole these kind of equations is LSODE. This method can be used in Maple.
Here, primary calculations show that the governed equation is second order nonlinear ODE and we propose two possible invariants to solve ODE. Overall, the primary numerical solution has shown perfect match with the exact solution.
Study of the Effect of Impeller Side Clearance on the Centrifugal Pump Performance Using CFD
Authors: Ayad A. Farid , Abdalla H. M. , Abou El-Azm A. 
Published: March 2016

Centrifugal pumps (CP) are probably among the most often used machinery in industrial facilities as well as in common practice. Compared to other types of rotating pumps, CP yield higher efficiency. In aerospace application reducing the weight of the CP impeller has the advantage of reducing mechanical stresses and enable using the CP at high number of revolution. In order to minimize the impeller weight the requirements to study and develop the CP with semi-open impeller appears. Using this type of impeller results in clearance between the impeller blades and the casing which degrade the centrifugal pump performance. The impact of this side clearance has not been deeply investigated in open literature.
The present paper is devoted to reveal more details about the impact of CP side clearance on its performance. This is done by numerically investigating the influence of the variation of the CP side clearance width (0:0.2 impeller width) on the CP performance parameters at different flow rates (0:5 Liter/s). These CP performance parameters include the pump head, efficiency, slip factor, blades loads and the internal flow structure.
3-D steady numerical simulation has been carried out using commercial software, ANSYS® CFX. The computational domain consists of four zones: inlet, side gab, impeller and volute with outlet. They are defined by means of the multi-reference frame technique. The impeller is situated in the rotating reference frame, while the inlet, side gab and outlet zones are in the fixed reference frame, and they are related to each other through the “frozen rotor” interface. The meshes of four computational domains are generated separately after performing mesh sensitivity analysis. The boundary conditions are set as total pressure at inlet and the mass flow at outlet. A no-slip condition is imposed at the wall boundary defined at the blade and casing. A turbulent, incompressible flow solver has been adapted using SST k–ω turbulent model.
The numerical simulation has been compared with own experimental results and a published empirical formulas to verify the numerical solution. The CFD results show an acceptable agreement with the results of the experimental work and the empirical formulas. It has been shown that the impeller side clearance have a great regression effect on the centrifugal pump performance. An explanation to the performance regression has been proposed based on the flow field feature. Performance regression could be attributed to the drop in the pressure difference between the impeller inlet and outlet. And the redistribution of the velocity inside the impeller channel and the side clearance.
Ranking and Optimization of CAC and HAC Leakage Using Pressure Controlled Models
Authors: Alissa Husam A. , Nemati Kourosh , Sammakia Bahgat , Ghose Kanad , Seymour Mark , King David , Tipton Russell 
Published: March 2016

In cold aisle containment (CAC) the supply of cold air is separated within the contained volume. The hot air exhaust leaves the IT and increases the room’s temperature before returning to the cooling unit. On the other hand, hot aisle containment (HAC) generates a cooler environment in the data center room as a whole by segregating hot air within the containment. Hot air is routed back to the cooling unit return by a drop ceiling or a chimney. Each system has different characteristics and airflow paths. For instance, leakage introduces different effects for CACs and HACs since the hot and cold aisles are switched.
This article utilizes data center measurements and containment characterization carried out circa April 2015 in the ES2 Data Center lab at Binghamton University. Details on the containment model include leakages at below racks, above racks, below CAC doors, between doors, and above doors. The model deploys the experimentally obtained flow curves approach for flow-pressure correlation.
Data center operators rely on the pressure differential to measure how much the IT is provided. Hence, in this study the level of provisioning was expressed in terms of pressure differentials between the hot and cold aisles. In this manner the model reflected real-life DC thermal management practices. This was done by integrating a pressure differential based controller to the cooling unit model. Leakages in each system are quantified and ranked based on a proposed LIF (Leakage Impact Factor) metric.
The LIF describes the transport contribution each leakage location has. This metric can be used by containment designers and data center operators to prioritize their sealing efforts or consider deploying the containment solution differently. Finally, a systematic approach is shown in which containment models can be used to optimize operations at the real-life site.
Gannon Exoskeleton for Arm Rehabilitation (G.E.A.R.)
Authors: Piovesan Davide , Arumugam Yuvarajan , Jackson Corey , Shanmugam Santhosh Kumar , Restifo Adam , Legters Kristine 
Published: March 2016

A low cost continuous passive motion (CPM) machine, the Gannon Exoskeleton for Arm Rehabilitation (GEAR), was designed. The focus of the machine is on the rehabilitation of primary functional movements of the arm. The device developed integrates two mechanisms consisting of a four-bar linkage and a sliding rod prismatic joint mechanism that can be mounted to a normal chair. When seated, the patient is connected to the device via a padded cuff strapped on the elbow. A set of springs have been used to maintain the system stability and help the lifting of the arm.
In this work a multi-body simulation was performed with the software SimWise 4D by Design Simulation Technologies (DST). The simulation was used to determine the stiffness of the springs in the mechanism to provide assistance to raising of the patient’s arm. Furthermore, the software can provide a finite element analysis of the stress induced by the springs on the mechanism and the external load of the arm. Finally, a physical prototype of the mechanism was fabricated using PVC pipes and commercial metal springs. Due to the low cost of fabrication, simplicity, and ease of adjustability, it is believed that the GEAR has the potential to provide effective passive movement to individuals who otherwise would not have access to post-operative or post-stroke rehabilitation therapy.
Augmenting an Educational and Research Human Robot Interaction Environment With a Multi-Obstacle Avoidance Algorithm
Authors: Ábrego Christopher E. 
Published: March 2016

In this manuscript, the development and current state of an inexpensive platform for educational purposes and research in the interaction between humans and robots (human-robot interaction) is described. The platform is based on the ubiquitous LabVIEW programming language and an in-house developed two degree of freedom non-holonomic robot. The platform includes multiple interaction modalities, which will be described, between the robot and the user.
The procedures followed for the successful software and hardware implementation are explicated. Furthermore, a demonstration of an obstacle avoidance path planning algorithm for a single obstacle is validated in hardware, as well as simulation demonstration of the multiple obstacle avoidance algorithm. These implementations to the platform further demonstrate the ease of augmenting the existing platform to additional modalities.
The algorithm uses a vision acquisition system to identify the location and size of an obstacle, in addition to orientation patterns and calibration points, in the workspace and generate the robot path to reach a desired goal while avoiding the obstacle. The manuscript describes into the current research of path planning in the presence of multiple obstacles. The development of a set of criteria, Generation Succession, Arrival Departure, and Side Consistency, for the algorithm are elucidated in the manuscript. The algorithm has been demonstrated to be successful in simulation by avoiding multiple obstacle in various layouts.
The Application of Axiomatic Design to Complex Wi-Fi Systems
Authors: Hintersteiner Jason D. 
Published: March 2016

Axiomatic Design is a technique that has been applied to multiple disciplines for enabling design, analysis, and troubleshooting of complex systems. In this paper, the principles of Axiomatic Design are applied to Wi-Fi networking. Wi-Fi is the information backbone for numerous applications, including Internet connectivity, video surveillance, data collection and inventory tracking in manufacturing and warehouse environments, patient location and health status monitoring in assisted living and hospital environments, along with numerous others. A Wi-Fi system consists of multiple access points working in tandem to provide seamless, high-speed, and high-quality wireless coverage to one or more wireless client devices. To implement such a network effectively, the Wi-Fi engineer must understand and control the interactions between multiple engineering disciplines, most notably information technology, network engineering, radio frequency physics, antenna design, and materials science. Technology development in this field is fast-paced, with new standards and capabilities being introduced into the market every couple of years. Additionally, the customer expectations (i.e. requirements) are changing as well once the Wi-Fi network is installed, as data demands from new types of devices like smartphones, tablets, and network appliances are introduced long after the original network was implemented.
This paper shows that there are three primary functional requirements for a Wi-Fi network, namely client usage type, coverage area, and client capacity. When designing, implementing, or troubleshooting a Wi-Fi network, there are four primary design parameters that can be controlled, namely AP antenna / model, location, channel, and transmission power. Axiomatic Design demonstrates that these four design parameters are coupled, and thus cannot be manipulated independently. Nevertheless, by effectively implementing Axiomatic Design techniques to define a set of best practices, these four key parameters can be decoupled and properly linked back to the requirements and constraints of the system to simplify the design, implementation, and troubleshooting of a Wi-Fi network.
Effects of Wall Shear and Rayleigh-Taylor Instabilities on a Gas-Liquid Interface in a High-Speed Multiphase Flow
Authors: Adam Carlton , Hadim Hamid 
Published: March 2016

A numerical simulation is performed to predict the multiphase flow structure of a slug of liquid salt water as it is accelerated through a launch tube by high-pressure, high-temperature gas. This effort is performed to support the design of recoilless launch systems, in which the momentum produced by the launch of a solid projectile is balanced by the ejection of a liquid countermass in the opposite direction. Careful design of the countermass can reduce the net recoil of the launch system to nearly zero, thus allowing higher launch energies to be obtained from relatively light platforms. Simulating the behavior of the liquid countermass during the launch cycle is important for predicting net recoil, as well as for calculating the overall performance of the launch system.
The current work builds on previous efforts to analyze the liquid slug ejection by considering the fluid system in three dimensions and by recognizing the importance of surface tension and mesh refinement at the gas-liquid interface. Effects of shear stress at the slug-wall interface are considered, as are Rayleigh-Taylor instabilities that arise due to the high acceleration and large density differences of the gas and liquid phases.
A transient 3D simulation of the launch event is performed using the VOF (volume of fluid) method to track the gas-liquid interface, while a realizable k-ε model is used to calculate turbulent viscosity in both the gas and liquid phases. The initial conditions of the simulation are that the liquid slug is initially at rest, and that a relatively flat and uniform gas-liquid interface discretely separates the two phases. The properties of the driving gas are calculated a priori using a separate combustion model. The driving gas enters the computational domain of the fluid model as an inlet boundary condition, specified by an entrance pressure as a function of time. The simulation is allowed to run until the bulk of the liquid slug has exited the tube into the atmosphere.
The predicted flow properties, including liquid volume fraction, pressure, velocity, and temperature fields as functions of time are reported. The predicted structure and velocity of the exiting slug are compared to measurements taken using high-speed video during empirical testing of a representative launch system. Gas pressures inside the tube during the launch cycle are compared to electronic pressure data collected from the same test. There is excellent agreement between the predicted and empirical exit velocity of the liquid slug, though the video data shows a higher degree of atomization of the liquid than is predicted by the model.