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Energy crisis and climate change are rocking the entire world at this moment. Refrigeration forms a major power consumer, ranging from domestic applications to industrial applications. Apart from a leading energy absorbing system, it also takes part in global warming by letting out harmful ozone depleting substances and hence turns against the environment. It is the right time to switch over from the conventional compressor based refrigeration systems. Magnetic refrigeration proves itself to be highly efficient and environmental friendly refrigeration system, making it to be the most...
This paper reports a computational investigation of water droplet emergence, growth, deflection, detachment and interaction in a cathode channel of a polymer electrolyte membrane (PEM) fuel cell. Though the PEM fuel cell is a promising technology for reducing CO2 emission, its performance is hampered at higher current densities due to water flooding. At higher current densities produced water floods the pores of gas diffusion layer (GDL) and flow channel preventing fresh oxygen to reach reactions sites. Therefore an effective water removal mechanism is essential for the efficient working of a...
This paper presents recent advances in the development and validation of the two-phase flow topology models implemented in CFD-BWR, an advanced Computational Fluid Dynamics (CFD) computer code that allows the detailed analysis of the two-phase flow and heat transfer phenomena in Boiling Water Reactor (BWR) fuel assemblies under various operating conditions. The local inter-phase surface topology plays a central role in determining the mass, momentum, and energy exchanges between the liquid and vapor phases and between the two-phase coolant and the fuel pin cladding. The paper describes the...
Two-phase flow phenomena inside a BWR fuel bundle include coolant phase changes and multiple flow regimes which directly influence the coolant interaction with fuel assembly and, ultimately, the reactor performance. The CFD-BWR code is being developed as a specialized module built on the foundation of the commercial CFD code STAR-CD which provides general two-phase flow modeling capabilities. New models describing two-phase flow and heat transfer phenomena specific for BWRs are developed and implemented in the CFD-BWR module. A set of experiments focused on two-phase flow and phase-change...
The leading-edge tubercles of humpback whale flippers have been shown to enhance hydrodynamic performance by increasing lift and decreasing drag poststall. To explore this effect, computational simulations of two models based on an idealized humpback whale flipper were conducted, one with a smooth leading edge and one with simulated leading-edge tubercles. Two different commercial computational fluid dynamics packages were used, STAR-CCM+ and SolidWorks Flow Simulation, and the results were compared with experiment. Numeric lift predictions in the nonstall region were reasonably accurate (...
It is known that bioprosthetic heart valves (BHVs) have better hemodynamics and lower thromboembolic events compared with their mechanical counterparts; however, patients implanted with BHVs still face the potential of such complications. The risk of a clinical thromboembolism is on average 0.7% per year in patients with tissue valves in sinus rhythm. In this study, we developed a computational fluid dynamic (CFD) model of a BHV implanted in an aortic root and investigated the BHV-induced platelet activation using a damage accumulation model previously applied to mechanical valves. The CFD...
A newly developed computational approach different from the conventional methods which are popularly adapted by the fan designers is employed to study the flow field and performance characteristics of an axial flow fan by using the commercial code (STAR-CD) of computational fluid dynamics. The new approach, which is termed the "downstream flow resistance" (DFR) method, engages the flow resistance of the fan test bench in the downstream area of the computational domain. Both the static and moving grids are employed in the computation. The results show at least three emphases. Firstly, the...
This paper aims to improve current understanding of flow structure and particle deposition in asthmatic human airways. A single, symmetric airway bifurcation, corresponding to generations 10–11 of Weibel’s model, is investigated through validated numerical simulations. The parent airway segment is modelled as a smooth circular tube. The child segments are considered asthmatic and their cross-section is modelled as a constricted tube with sinusoidal folds uniformly distributed along the circumference. The flow structure and particle deposition pattern for normal (i.e., healthy) and asthmatic...
In conjunction with the NASA-Gulfstream and Gulfstream-University of Florida wind tunneltesting of a generic nose landing gear model, Computational Aero-Acoustics research was conducted at Gulfstream using the commercial Navier-Stokes Finite Volume CFD solver STAR-CCM+. The simulation modeled the ¼ scale G550 nose landing gear mounted in the NASA Basic Aerodynamics Research Tunnel (BART) wind tunnel test section. The model was run at the 0.166 Mach Number condition on the simplified nose landing gear with the gear cavity closed. Prior to simulation execution,dynamic pressure probes were...

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