Total pressure

About: Total pressure is a research topic. Over the lifetime, 5199 publications have been published within this topic receiving 66658 citations.

Numerical Simulation of the Transient Flow in a Radial Flow Pump during Stopping Period

Abstract: Three-dimensional (3-D) unsteady incompressible and non-cavitating flow in a radial flow pump during the rapid stopping period was numerically studied by CFD. The dynamic mesh (DM) method combined with non-conformal grid boundaries was applied to simulate the transient stopping process. In order to exclude the uncertainty of the unsteady inlet and outlet boundaries, a loop pumping system was established, which was composed of pipes, a reservoir with an air part on the top, and a driving pump. Simulations were performed based on the standard k-e turbulence model and volume of fluid (VOF) model. Results showed that the air part in the reservoir approximated real conditions when using the VOF model. Pressure fluctuations were reduced and a sharp increase of pressure at the inlet of the pump was observed at the beginning of the stopping period. Specific transient characteristics, such as the flow-rate, head and efficiency, were analyzed during the deceleration period and compared with corresponding quasi-steady results. The deviation of the quasi-steady hypothesis in predicting the transient stopping process of radial flow pumps is thought to be caused by differences in the predicted vortex in the impeller. The transient curve showing the relationship between the instantaneous flow coefficient and total pressure rise coefficient was analyzed and compared with the quasi-steady curve. The two curves had a crossover point when the stall just occurs in the impeller during the transient process. Simulation results were also compared and validated using published data.

Migration of Combustor Exit Profiles Through High Pressure Turbine Vanes

Abstract: The high pressure turbine stage within gas turbine engines is exposed to combustor exit flows that are nonuniform in both stagnation pressure and temperature These highly turbulent flows typically enter the first stage vanes with significant spatial gradients near the inner and outer diameter endwalls These gradients can result in secondary flow development within the vane passage that is different than what classical secondary flow models predict The heat transfer between the working fluid and the turbine vane surface and endwalls is directly related to the secondary flows The goal of the current study was to examine the migration of different inlet radial temperature and pressure profiles through the high turbine vane of a modern turbine engine The tests were performed using an inlet profile generator located in the Turbine Research Facility at the Air Force Research Laboratory Comparisons of area-averaged radial exit profiles are reported as well as profiles at three vane pitch locations to document the circumferential variation in the profiles The results show that the shape of the total pressure profile near the endwalls at the inlet of the vane can alter the redistribution of stagnation enthalpy through the airfoil passage significantly Total pressure loss and exit flow angle variations are also examined for the different inlet profiles