Numerical Prediction Of Torque On Guide Vanes In A Reversible Pump-Turbine Turbine and pump mode operation
The paper presents the numerical flow analysis of the torque on guide vanes pivots in reversible pump-turbine (PT) in turbine and pump mode operation. Flow conditions in a typical PT often point out the importance of the unsteadiness of the flow, first of all because of its instability caused by the viscous effects – the boundary layer separation, vortex spreading and the influence between rotating and non-rotating parts. The detailed analysis of the time dependent distribution of torque on guide vanes is presented. The numerical analysis was performed for complete pump-turbine with various turbulence models. The numerical results were compared with the experimental results. Keywords—water turbine, reversible pumpturbine, CFD, guide vanes, dynamic chyracteristics
Development and Application of SST-SAS Turbulence Model in the DESIDER Project
The paper reports on the current state of the SST-based Scale-Adaptive Simulation model (SST-SAS model), and summarises the validation activity performed with this model in the course of the DESIDER project. The turbulence-resolving capability of the SST-SAS model has been validated with the official project test cases, covering both the underlying generic flows as well as practical aerodynamic applications. Among the latter ones are also the two aero-acoustic test cases of industrial interest. The paper includes a brief description of the current state of the SST-SAS model, as well as the illustrating test case results. Potentials of the SAS approach are briefly discussed, as well as its position amongst the other transient simulation methods.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.