Backflow From Inducer and Its Dynamics

Tsujimoto, Yoshinobu; Horiguchi, Hironori; Qiao, Xiangyu

doi:10.1115/fedsm2005-77381

Cited by 12 publications

(8 citation statements)

References 0 publications

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“…2) The amplitude of the pressure oscillations decreases as the tip blade clearance increases, and the maximum value of the oscillation at the blade passage frequency ( 50 Hz, phenomenon named SRC) decreases significantly when the clearance varies from 0.8 to 2 mm (this result is in agreement with that reported in the open literature, i.e., in [35]). …”

Section: Discussionsupporting

confidence: 88%

“…The phenomena are evident only at relatively high cavitation numbers. Frequency f2, as mentioned before, shows the characteristics of a one-lobe corotating instability: it is likely related to the backflow rotation at 0:2 , as reported in other works [35]. Frequency f4 is an axial phenomenon, for which the characteristics are different from those found for other well-known oscillations.…”

Section: B Flow Instabilities At Higher Clearancesupporting

confidence: 60%

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Effect of Tip Clearance on the Performance of a Three-Bladed Axial Inducer

Torre¹,

Pasini²,

Cervone³

et al. 2011

Journal of Propulsion and Power

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This paper illustrates the results of an experimental campaign conducted in the Cavitating Pump Rotordynamic Test Facility. Tests have been carried out at two values of the blade tip clearance on the three-bladed DAPAMITO3 inducer, designed by means of a reduced-order model, with geometry and noncavitating performance representative of typical space rocket inducers. Different cavitating behaviors have been observed at different values of the blade tip clearance, particularly near breakdown conditions. The intensity of pressure oscillations tends to decrease as the tip blade clearance increases, and cavitation-induced azimuthal flow instabilities appear to be more sensitive to changes of the blade tip clearance than axial flow instabilities. Finally, the presence of backflow seems to have a stabilizing effect on rotating cavitation instabilities. Nomenclature c % = tip clearance/mean blade height ratio c % =h m f1; 2; . . . = name of instability h m = mean blade height, m n = number of lobes p in = inlet static pressure, Pa p V = vapor pressure, Pa Q = volumetric flow rate, m 3 =s Re = Reynolds number; 2r 2 T = r T = inducer tip radius, m b = blade angle evaluated with respect to the azimuthal direction, rad xy = coherence function p = static pressure rise across inducer, Pa = angular spacing between transducers, rad = tip clearance, m = kinematic viscosity, m 2 =s = liquid density, kg=m 3 = cavitation number; p 1 p V =0:5 2 r 2 T = flow coefficient; Q=r 3 T D = design flow coefficient ' = phase of cross spectrum, rad = static head coefficient; p= 2 r 2 T = inducer rotational speed, rad=s

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Section: Discussionsupporting

confidence: 88%

Section: B Flow Instabilities At Higher Clearancesupporting

confidence: 60%

Effect of Tip Clearance on the Performance of a Three-Bladed Axial Inducer

Torre¹,

Pasini²,

Cervone³

et al. 2011

Journal of Propulsion and Power

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“…It can also have a very important effect on cavitation instabilities. 11,15 The typical flow structure around an inducer is characterized by a backflow region and vortices. The backflow region is created by leakage flow from the tip clearance.…”

Section: Cavitating Regimementioning

confidence: 99%

Numerical and experimental study of cavitating flow through an axial inducer considering tip clearance

Campos–Amezcua

Khelladi

Mazur-Czerwiec

et al. 2013

Proceedings of the Institution of Mechanical Engineers, Part A:

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This paper presents three-dimensional numerical simulations and experimental investigations of cavitating flow through an axial inducer. Particularly, this work focuses on the influence of radial tip clearance on cavitation behavior. Numerical analysis was carried out on two different configurations: first, the inducer was modeled without taking tip clearance into consideration. Later, the inducer was modeled with nominal tip clearance and some modifications of this. It was found that radial tip clearance has a significant influence on the overall inducer performance in the non-cavitating regime because of the small size of the inducer. Moreover, the effects of radial tip clearance are strong in inducer cavitation behavior. Numerical results and experimental data with nominal tip clearance were compared in cavitating and noncavitating regimes and these were discussed. The cavitation model used for calculation is based on a single-fluid multiphase flow method, assuming thermal equilibrium between phases. It is based on the classical conservation equations of the vapor phase and a mixture phase, with mass transfer due to cavitation appearing as a source and a sink term in the vapor mass fraction equation. Mass transfer rates are derived from the Rayleigh-Plesset model for bubble dynamics.

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“…Alternate blade cavitation is a phenomenon in which the cavitation length on the blades changes alternately from blade to blade. According to (Tsujimoto, 2005) the alternate blade cavitation starts to develop when the cavitation length exceeds about 65% of the blade spacing: (l cav /h)≥65%. So, the incidence angle to the neighbouring blade decreases and, hence the cavitation length on the neighbouring blade decreases also.…”

Section: Stable Blade Cavitationmentioning

confidence: 99%