Blood Flow in the Aortic Arch

Tim David and R. Bagnall of the University of Leeds used FIDAP to model the 3D time- dependent flow emanating from bileaflet valves implanted in the aortic position and compared the predictions with naturally occurring flows. The results indicated that the valve induces regions of high shear stress on the vessel wall, created by vortex sheets developed downstream of the valve, with implications for damage to the tissues lining the aorta. The CFD simulations also indicated how the valve design might be improved to avoid flow-induced problems.

Figure 1. Wall shear stress on the aortic arch blood vessel, predicted by FIDAP, illustrating flow-induced problems from a valve implant. Courtesy of the School of Mechanical Engineering, University of Leeds. (Postprocessing using Ensight by CEI.)

Optimizing Waste Incinerator Flows

Ansaldo Volund A/S of Denmark produces boilers for waste incineration processes and uses FLUENT/UNS for flow optimization. Traditionally, designs have been based on limited data, and flow-related performance problems have been observed, from corrosion of tube walls to structural problems arising from undesirable flame structures.

Ansaldo Volund used FLUENT/UNS to understand flow-related problems in an existing waste incinerator. The CFD prediction identified the sources of corrosion observed at the plant and helped the designers to optimize a design solution, using noses in the first and second passes. Due to the success of the furnace simulations, demand for CFD within the company has risen considerably.

Figure 2. FLUENT/UNS prediction of temperature distribution in the improved incinerator. Design changes helped to minimize flow-related erosion problems. Courtesy of Ansaldo Volund A/S

Validating Flow Simulation for a Francis Turbine Runner

This outstanding paper presented by CKD Blansko dealt with the study of 3D flow in a medium specific-speed Francis turbine runner using FLUENT/UNS. The simulations were performed as steady-state, viscous, turbulent flow using a rotating frame of reference and a hexahedral mesh. Comparison to experimental data was excellent over a range of operating conditions, providing validation that FLUENT/UNS is well suited to contribute to water turbine performance improvement. Hex meshing, in combination with mesh adaption, was highlighted as contributing to the solution accuracy and efficiency.

Figure 3. Flow analysis of the Francis turbine runner. Hanging node adaption was used to improve the prediction of leading edge vortices. Courtesy of CKD Blansko Engineering a.s.

FluentNEWS