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Rocket Engines
Published in Ahmed F. El-Sayed, Aircraft Propulsion and Gas Turbine Engines, 2017
Blade tip diameter is selected to optimize the (Ut/C0) for efficiency within the blade height-to-diameter performance limits and within the tip speed structural limits. If the blade height-to-diameter ratio gets too small, the tip clearance and secondary flow losses become large, decreasing the turbine efficiency.
Fixed displacement gerotor oil pump (FDOP): a survey
Published in International Journal of Ambient Energy, 2022
V.T. Gannesh, R. Sivakumar, G. Sakthivel
In gerotor tip to tip/tip/teeth clearance, radial clearance and axial clearance are the three major clearances which influence the pump performance through leakage which, in turn, influences the pumping efficiency. These clearances may also cause shock or collision among pump components resulted in huge noise, more stress fluctuations and reduced pump life. Iudicello and Mitchell (2002). Tip clearance is the gap between two mating rotors at maximum pocket volume on the carryover land which leads to the leakage of fluid from maximum pocket volume to inlet port due to the back pressure from the outlet port. Radial clearance is the gap between the outer rotor outer face to body bore face. Axial clearance or face to face clearance is the gap between rotor face to body face and rotor face to cover face which leads to the leakage of flow from the outlet port to inlet port. Figure 4 shows the tip, radial and axial clearances.
Influence of different operating conditions on centrifugal compressor surge control with active magnetic bearings
Published in Engineering Applications of Computational Fluid Mechanics, 2019
Xudong Guan, Jin Zhou, Chaowu Jin, Yuanping Xu, Hengbin Cui
From Equation (11), we can draw the graph of the characteristic curve affected by the tip clearance, as shown in Figure 6. It can be clearly seen that the pressure rise and mass flow will change as the tip clearance changes. When the mass flow rate is constant, the pressure rise of the compressor slowly decreases with the increase in the tip clearance, that is, the output pressure decreases. The reason is that as the tip clearance increases, the compressor efficiency decreases. On the contrary, the pressure rise increases as the tip clearance is reduced. It can also be seen that the compressor characteristic curve changes linearly with the tip clearance.
Numerical study of the radiation effect on the jet array impinging heat transfer in a feeding pipe
Published in Numerical Heat Transfer, Part A: Applications, 2018
Junkui Mao, Tian Yao, Xingsi Han, Zhenzong He, Kang He
Tip clearance control is an effective way to reduce the aerodynamic loss and the specific fuel consumption in the turbine aero-engine. Previous study shows that more than one-third of turbine loss can be caused by the tip leakage flow in some situations [1]. The ratio of low pressure turbine tip clearance to blade height reduced by 1% could lead to the turbine efficiency increase by 0.8–1.2%, as a result of that, the fuel consumption could be reduced by about 2% [2].