Total pressure

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

Developing a Combustor Simulator for Investigating High Pressure Turbine Aerodynamics and Heat Transfer

Abstract: Within a gas turbine engine, the high pressure turbine vanes are subjected to very harsh conditions from the highly turbulent and hot gases exiting the combustor. The temperature and pressure fields exiting the combustor dictate the heat transfer and aero losses that occur in the turbine passages. To better understand these effects, the goal of this work is to develop an adjustable combustor exit profile simulator for the Turbine Research Facility (TRF) at the Air Force Research Laboratory (AFRL). The TRF is a high temperature, high pressure, short duration blow-down test facility that is capable of matching several aerodynamic and thermal non-dimensional engine parameters including Reynolds number, Mach number, pressure ratio, corrected mass flow, gas-to-metal temperature ratio, and corrected speed. The research objective was to design, install, and verify a non-reacting simulator device that provides representative combustor exit total pressure and temperature profiles to the inlet of the TRF turbine test section. This required the upstream section of the facility to be redesigned into multiple concentric annuli that serve the purpose of injecting high momentum dilution jets and low momentum film cooling jets into a central annular chamber, similar to a turbine engine combustor. The design of the simulator allows for variations in injection levels to generate turbulence and pressure profiles. It also can vary the dilution and film cooling temperatures to create a variety of temperature profiles consistent with real combustors. To date, the design and construction of the simulator device has been completed. All of the hardware has been trial fitted and the flow control shutter systems have been successfully installed and tested. Currently, verification testing is being performed to investigate the impact of the generated temperature, pressure, and turbulence profiles on turbine heat transfer and secondary flow development. NOMENCLATURE A flow area or surface area cp specific heat D hole diameter G mass flow velocity, ff A m G &

Numerical Study of Internal Flow Structures in a Sweeping Jet Actuator

Abstract: This study focuses on the generation and interaction of internal flow structures, jet oscillation process, and pressure drop mechanism of a Sweeping Jet Actuator. Timedependent numerical analysis was performed over a range of inlet mass flow rates. The effect of varying inlet mass flow rate on the sweeping jet oscillation frequency was calculated and a strong agreement was found with the experimental measurements. The velocity, temperature and pressure fields are provided. The complex flow field inside the Sweeping Jet Actuator for half an oscillation cycle are presented by velocity magnitude and total pressure contours. Formation of vortices from sharp corners in the actuator core surfaces were observed, and their role in jet oscillation is shown.

Flow Separation Prevention on a Turbine Blade in Cascade at Low Reynolds Number

Abstract: : The problem of flow separation from a low pressure turbine blade was investigated The operating conditions under which the separation occurred were documented through measurement of surface pressure coefficients, boundary layer velocity and turbulence profiles, total pressure loss coefficient and wake velocity momentum deficit Three different means for reducing the losses associated with the flow separation were also investigated A boundary layer trip, dimples, and V-grooves were studied as passive means requiring no additional energy to reduce the separation losses The boundary layer trip was only successful for an inlet and axial chord Reynolds number of 50k with a reduction in loss coefficient of 582% Three sets of dimples were tested with the placement of each at axial chord locations of 50%, 55%, and 65% The dimples provided reductions in the loss coefficient for Reynolds numbers of 50k, 100k, and 200k ranging from 51% (Re = 100k, freestream turbulence level of 4%) to 517% (Re = 50k, freestream turbulence level of 4%) Two sets of V-grooves were tested with axial chord start locations of 55% and 60% The V-grooves provided smaller reductions in loss coefficient than the dimples Boundary layer profiles, total pressure loss coefficients, and wake velocity momentum deficits are presented for the three passive modifications

Apparatus for fusion joining of thermoplastic pipes

Abstract: The apparatus increases the hydraulic pressure in rams 16 until one pipe moves towards a heater plate 14. The movement is detected by a limit switch 26 and a microprocessor-based control system 28 adds a pre-programmed value of pressure to that pressure which caused the movement (drag pressure). The total pressure is applied to force the pipe ends against a heater plate 14 to form end beads (bead-up). After heating for a pre-programmed period the control system automatically initiates plate retraction and forces the pipe ends together (fusion) for another programmed period. The applied pressure is the sum of the recorded drag pressure and a pre-programmed added pressure. Operator judgement of bead size, pressures and time periods is eliminated. Pressurised fluid is supplied to the rams 16 from a pump and accumulator combination. The sense of ram motion is determined by changeover valves controlled by the control system 28.