Self-Oscillations (Surging) of a Single-Stage Centrifugal Pump in the Cavitation Regime and Their Damping

Gotsulenko, V. V.; Gotsulenko, V. N.

doi:10.1007/s10891-013-0911-2

Cited by 2 publications

(4 citation statements)

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“…It should be noted that the positiveness of the acoustic energy A > 0 of the pump in question confirms the presence of the ascending branch or its ascending branchings on its head characteristic. The setup of self-oscillations (surging) of a screw pump when the condition ∂H scr ⁄ ∂P in ≠ 0 leading to a branching of its head characteristic is observed has been confirmed in [10].…”

Section: Introductionmentioning

confidence: 73%

“…The hydraulic loss in the pipeline of the oscillatory circuit R(Q) is disregarded because of its insignificance. The working portion of the characteristic of a blower F(Q) in the region of cavitation branchings is determined with the known dependence Δh = ψ(Q) [10]. According to surging theory, periodic (self-oscillatory) solutions of the system of equations (1) correspond to a closed isolated solution (limiting cycle) of the equation of integral curves…”

Section: Introductionmentioning

confidence: 99%

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Distinctive feature of self-oscillations (surging) of impeller pumps

Gotsulenko

2012

J Eng Phys Thermophy

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It has been established experimentally and confirmed analytically that before the stall of a centrifugal impeller pump, self-oscillations (surging) of the pump are set up in the region of ascending cavitation branchings of its monotonically decreasing head characteristic. Beyond this region, the pumping mode of such a pump is absolutely stable. It has been established that changes in the nonstationary operation of a centrifugal impeller pump produced by variation of its wave resistance are diametrically opposite in character in cavitation and cavitation-free modes. Introduction.It is well known that the reason for excitation of longitudinal self-oscillations (surging) of impeller pumps is the formation of an ascending branch on their head characteristic H(Q) [1]. In the case of the nonstationary operation of an impeller pump, unlike a compressor, elimination of lumped air caverns (volumes) in the hydraulic system leads to such a marked decrease in the amplitude of self-oscillations of the pump that it becomes possible to experimentally determine the ascending (unstable) branch of its head characteristic and the cavitation branchings of this characteristic H(Q, Δh). Also, it is known that in hydraulic systems, self-oscillations are set up before the failure (stall) of an impeller pump [2]. In the operation of a screw centrifugal pump feeding the propellant components to a liquid-propellant rocket engine, i.e., of a short-life pump, self-oscillations of such a pump are excited even in the absence of the ascending branch on its head characteristic. The setup of self-oscillations of a screw centrifugal pump with a stable monotonically decreasing head characteristic has been investigated with a number of models in [3] and the operating mode of such a pump due to the setup of the so-called "cavitation" self-oscillations has been considered. A nearly stall pressure is often taken as the permissible inlet pressure of a centrifugal impeller pump with a short life [3,4]. It is stated [3, 5] that cavitation self-oscillations cannot be set up in modes similar to cavitation stall where the pump operation is unstable. In [6], it is assumed that cavitation self-oscillations are characteristic not only of centrifugal impeller pumps but of screw centrifugal pumps as well.Experimental investigations of a centrifugal impeller pump with a monotonically decreasing head characteristic [7] have shown that before the stall where the head of the pump is dependent on both the volumetric rate of water flow Q and the pressure on the pump inlet P in , the characteristic H(Q) branches out. Surging occurs in the region of the ascending cavitation branchings of this characteristic H(Q, Δh), where the derivative is ∂H ⁄ ∂Q > 0, and self-oscillations are dependent on the reactance of the oscillatory circuit. Thus, the setup of oscillations of the centrifugal impeller pump before its stall is attributable to the surging in the region of ascending cavitation branchings of the pump's head characteristic. We were unable to find experimentally cavitat...

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Distinctive feature of self-oscillations (surging) of impeller pumps

Gotsulenko

2012

J Eng Phys Thermophy

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“…Системы типа (1.5) возникают во многих физических приложениях. Так, в частности, проблема возбуждения продольных автоколебаний в замкнутой гидросистеме с воздушной подушкой на входе в лопастной насос [7] и автоколебания (помпаж) одноступенчатого центробежного насоса в режиме кавитации [8] приводят к рассмотрению именно системы вида (1.4) или (1.5).…”

Section: в в гоцуленкоunclassified

“…Далее величину Z = β α будем рассматривать как бифуркационный параметр. В физических приложениях данный параметр называется волновым сопротивлением системы [7,8]. Критическое значение Z kr определяется из условия tr (J)| Z=Z kr = 0 ⇔ Z kr = 2 kry 1 (y * − y 1 ).…”

Section: примерыunclassified

Self-oscillations in implicit singularly perturbed dynamical systems on the plane

Gotsulenko¹

2014

Nelin. Dinam.

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Для неявно сингулярно возмущенных автономных систем обыкновенных дифференциальных уравнений второго порядка найдены некоторые достаточные условия существования у них релаксационных периодических решений (автоколебаний), определяемых с помощью некоторой вспомогательной динамической системы, реализующей скользящий режим. Показано, что определенные таким образом периодические движения обладают типичными свойствами релаксационных автоколебаний, определяемых автономными системами обыкновенных дифференциальных уравнений с малым параметром при старшей производной. Ключевые слова: неявно сингулярно возмущенная система, скользящий режим, релаксационное периодическое решение, автоколебания

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Self-Oscillations (Surging) of a Single-Stage Centrifugal Pump in the Cavitation Regime and Their Damping

Cited by 2 publications

References 1 publication

Distinctive feature of self-oscillations (surging) of impeller pumps

Distinctive feature of self-oscillations (surging) of impeller pumps

Self-oscillations in implicit singularly perturbed dynamical systems on the plane

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