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Ultrahigh Vacuum
Published in Marsbed H. Hablanian, High-Vacuum Technology, 2017
Until a few years ago, turbopumps were made with rather low compression ratio for light gases. This poor compression ratio for hydrogen and helium is due to practical engineering considerations—primarily the limited number of stages and the issue of size and cost. In older pumps, the residual gas at the inlet to the pump consisted mainly of hydrogen (over 99%, reported by J. Henning). Most of the hydrogen originated from the oil-sealed mechanical backing pumps. Because of bearing lubrication and backing by oil-sealed mechanical pumps, the operation of turbopumps requires certain precautions. To prevent contamination of the vacuum system the pump must be vented during deceleration. A special, automatically acting, small valve is often provided for this purpose at the midsection of the pump. Also, the vacuum system should not be exposed to an operating mechanical pump environment when the turbomolecular pump is stopped. One of the advantages of turbopumps is the possibility of omitting inlet valves (involving expense and additional outgassing), because, unlike operating vapor jet pumps, turbopumps can be exposed to atmosphere without subsequent malfunction or damage.
Rocket Engines
Published in Ahmed F. El-Sayed, Aircraft Propulsion and Gas Turbine Engines, 2017
The main element in a pump-fed system is the turbopumps. A turbopump is a gas turbine that comprises basically two main components: a rotodynamic pump that delivers fuel or oxidizer to the thrust chamber and a driving turbine, usually both mounted on the same shaft, or sometimes geared together. The purpose of a turbopump is to produce a high-pressure fluid for feeding a combustion chamber where propellants react and produce high-temperature gases. A turbopump can comprise either a single- or multistage centrifugal pump or multistage axial flow pump.
An efficient approach for the diagnosis of faults in turbo pump of liquid rocket engine by employing FFT and time-domain features
Published in Australian Journal of Mechanical Engineering, 2018
N. Aiswarya, S. Suja Priyadharsini, K. S. Moni
Turbo pump is one of the major components in the propulsion system of space rocket engines. Turbo pump converts the low pressure propellant to high pressure propellant and supplies to the combustion chamber where it gets ignited. In this work, the vibration data-sets of Vikas engine turbo pump used in Indian Launch vehicles like PSLV, GSLV is taken for study. Turbo pump consists of three centrifugal pumps driven by a common turbine. The rotating assembly of Turbo Pump consists of impellers, bearings, shafts and seals. Turbo pump rotates at a speed of 10,000 RPM. The rotating assembly which rotates at its natural frequency is called critical speed. The natural frequency and the rotational speed are expressed in hertz and RPM, respectively. Kamijo (2013) has dealt with the turbo pump elaborately. In industrial pumps, the rotational speed is well below the critical speed. But in launch vehicle turbo pumps, the rotational speed is closer to the critical speed. Running the turbo pump closer to the critical speed is very dangerous when the vibration level of any one of the rotational components exceeds the normal value. The factors like rotor unbalance, shaft misalignment, wear and rub create more vibration.
Design and Analysis of Embedded I&C for a Fully Submerged Magnetically Suspended Impeller Pump
Published in Nuclear Technology, 2018
Alexander M. Melin, Roger A. Kisner
Magnetic bearings have been in use for decades and are well suited to challenging environments. They have seen widespread use in cryogenic pumps and expanders, turbopumps, steam turbines, hot helium blowers, flywheel energy storage, high-speed transportation, levitating trains, and high-speed machinery.12–14 They are also commonly used in aerospace gyroscopes, momentum wheels, and vacuum turbopumps. Currently, magnetic bearings operate in air or a vacuum, and the external forces on the shaft are not considered because they are small or treated as a bounded external force when designing the magnetic bearing controller. However, in a canned pump design like the ORNL high-temperature conceptual pump, the shaft will experience nonlinear hydrodynamic forces that can exhibit complex behavior such as speed-dependent Taylor-Couette flow bifurcation.15 Existing models and control design techniques for magnetic bearings are not sufficient for systems with these nonlinear hydrodynamics.