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Background: Endothelial shear stress is one of the local hemodynamic factors suspected in the development of coronary atherosclerosis in bifurcation lesions. In patients with provisional stenting, the endothelial shear stress (SS) distribution is unknown. Objective: The aim of this study was to investigate the magnitude and distribution of the SS of coronary bifurcation lesions stenting by the provisional approach. Methods: Ten consecutive patients were included in this study. Quantitative coronary analysis, flow study, and three-dimensional computational analysis with the aid of the...
This investigation is a continuing analysis of the cooling performance and aerodynamic properties of a rear mounted cooling module on a semi-generic commercial vehicle, which was carried out by Larsson, Löfdahl and Wiklund . In the previous study two designs of the cooling package installation were positioned behind the rear wheelhouse and the results were compared to a front mounted cooling module. The investigation was mainly focused on a critical cooling situation occurring at lower vehicle speeds for a local distribution vehicle. The conclusion from the study was that the cooling...
The most common fan model to use in commercial CFD software today is the Multiple Reference Frame (MRF) model. This is at least valid for automotive under hood applications. Within the industry, for this typical application, this model is commonly known to under predict performance. This under prediction has been documented by the authors' of this paper in SAE paper 2009-01-0178 and VTMS paper 2009-01-3067. Furthermore has this been documented by S.Moreau from Valeo in “Numerical and Experimental Investigation of Rotor-Stator Interaction in Automotive Engine Cooling Fan Systems”, ETC, 7th...
The conjugate heat transfer methodology has been employed to predict the flow and thermal properties including the metal temperature of a NASA turbine vane at three operating conditions. The turbine vane was cooled internally by air flowing through 10 round pipes. The conjugate heat transfer methodology allows a simultaneous solution of aerodynamics and heat transfer in the external hot gas and the internal cooling passages and conduction within the solid metal, eliminating the need for multiple / decoupled solutions in a typical industry design process.The model of about three million...
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 (...

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