Analyses of Transient Events in Complex Valve and Feed Systems

Ahuja, Vineet; Hosangadi, Ashvin; Cavallo, Peter A.; Daines, Russell

doi:10.2514/6.2005-4549

Cited by 8 publications

(7 citation statements)

References 4 publications

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“…4 shows the configuration of orifices used in the calculations. Case A is the same orifice as in reference [10] selected as a baseline one to compare the numerical accuracy of calculation with experimental data. Cases B and C are chosen with modifications from orifice shape A, as shown in Fig.…”

Section: Flow Instability In Various Orifice Configurationsmentioning

confidence: 99%

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Flow instability due to cryogenic cavitation in the downstream of orifice

Lee

Roh

2009

J Mech Sci Technol

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Flow instability in LRE (liquid rocket engine) occurs due to various reasons such as flow interactions with valve, orifice and venturi, etc. The inception of cavitation, especially in the propellant feeding system, is the primary cause of mass and pressure oscillations because of the cyclic formation and depletion of cavitation. Meanwhile, the main propellant in a liquid rocket engine is the cryogenic fluid, which properties are very sensitive to temperature variation. And the change of propellant properties to temperature variation by thermodynamic effect needs to be properly taken into account in the flow analysis in order to understand basic mechanisms for cryogenic cavitation. The present study focuses on the formation of cryogenic cavitation by using the IDM model suggested by Shyy and coworkers. The flow instability was also numerically investigated in the downstream of orifice with a developed numerical code. Calculation results show that cryogenic cavitation can be a primary source of flow instability, leading to mass fluctuations accompanied by pressure oscillations. The prediction of cavitation in cryogenic fluid is of vital importance in designing a feeding system of an LRE.

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Section: Flow Instability In Various Orifice Configurationsmentioning

confidence: 99%

“…The mass flow rate is fixed as 130 lbm/sec and inlet pressure is 1.0E6 Pa. Orifice diameter is set as 0.1524m from reference [10]. Also, grid points are made with 246x80 in the calculation.…”

Section: Flow Instability In Various Orifice Configurationsmentioning

confidence: 99%

Flow instability due to cryogenic cavitation in the downstream of orifice

Lee

Roh

2009

J Mech Sci Technol

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“…For the propellant feeding system of cryogenic launch vehicles, much work has been performed on the optimal design and unsteady flow characteristics [26][27][28][29][30][31][32][33][34][35][36][37][38]. For H-IIB launch vehicles in Japan, both liquid hydrogen (LH 2 ) feed lines and liquid oxygen (LOX) feed lines each consist of two independent feed pipes from a tank [26].…”

Section: Introductionmentioning

confidence: 99%

“…This configuration was selected to avoid interference between two feed lines. Ahuja [28] reported that conveying components could experience cavitation-based instability flow, thus leading to large-scale shedding of vapor clouds and pressure oscillations. They presented simulations of the diverse unsteady phenomenon associated with the valve and feed systems that included a valve stall, valve timing studies, as well as two different forms of cavitation instabilities.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Instability Flow Behaviors of Liquid Oxygen in a Feeding Pipeline with a Five-Way Spherical Cavity

Xie

Xia

Chen³

et al. 2020

Energies

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The hydrodynamic information of liquid oxygen in the conveying pipeline of cryogenic launch vehicles directly determines the reliability of the operation of the turbopump. A 0.09 MPa anomalous pressure fall phenomenon in the feeding system has been observed during the flight and run test of a cryogenic rocket with four parallel engines. In previous work, we set up a full-scale experimental system with liquid oxygen as media. The anomalous pressure fall was successfully reproduced. Experimental studies of this phenomenon suggest that the problem might be associated with vortices into the five-way spherical cavity structure. The objective of this study was to determine the three-dimensional instability flow by computational methods to identify and better understand the anomalous pressure fall phenomenon. A numerical model developed by the turbulent conservation equations was validated by experimental data. The generation and evolution of vortices into the five-way spherical cavity of feeding pipelines was captured. It was found that the root cause of the instability flow causing the unusual pressure fall is the formation of a spindle-like vortex into the five-way spherical cavity due to disturbance of the inlet liquid oxygen. The results showed that there is a mirror-symmetrical four-vortices structure in the absence of disturbance, in which the liquid oxygen pressure fall with the rise of the Reynolds number is in good agreement with the predicting values calculated by a set of traditional empirical correlations. In the case of the specific operating conditions, it is also consistent with the experimental results. When the disturbance occurs at the inlet of the spherical cavity, the mirror-symmetrical four-vortices structure gradually evolves into the mirror-symmetrical two-vortices structure. When the disturbance is further enhanced, the mirror-symmetrical two-vortices structure merge with each other to form a spindle-like vortex, which is similar to the Rankine vortex structure. The pressure fall on the corresponding side of the spindle-like vortex core reduces abnormally, and is about 0.07 MPa, which is consistent with the experimental data under certain disturbance conditions. Moreover, it was found that the spindle-like vortex is a stable eddy structure, and would continue to exist once it is formed, which could also not disappear with the removal of the disturbance.

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“…This is important in a test stand environment where transient operation of the test facilities can take a significant fraction of the total test time. The work covering this aspect of valve modeling including a description of the grid motion methodology is reported in a companion paper 12 . The valve modeled above has a plug profile typical of a valve type referred to as an ``equal percentage plug'', which indicates that the percentage change in mass flow with valve position is constant through much of the operating range of the plug.…”

Section: Aiaa-2005-4543mentioning

confidence: 99%

Computational Modeling of Liquid and Gaseous Control Valves

Daines

Ahuja

Hosangadi

et al. 2005

41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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In this paper computational modeling efforts undertaken at NASA Stennis Space Center in support of rocket engine component testing are discussed. Such analyses include structurally complex cryogenic liquid valves and gas valves operating at high pressures and flow rates. Basic modeling and initial successes are documented, and other issues that make valve modeling at SSC somewhat unique are also addressed. These include transient behavior, valve stall, and the determination of flow patterns in LOX valves. Hexahedral structured grids are used for valves that can be simplifies through the use of axisymmetric approximation. Hybrid unstructured methodology is used for structurally complex valves that have disparate length scales and complex flow paths that include strong swirl, local recirculation zones/secondary flow effects. Hexahedral (structured), unstructured, and hybrid meshes are compared for accuracy and computational efficiency. Accuracy is determined using verification and validation techniques.

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Analyses of Transient Events in Complex Valve and Feed Systems

Cited by 8 publications

References 4 publications

Flow instability due to cryogenic cavitation in the downstream of orifice

Flow instability due to cryogenic cavitation in the downstream of orifice

Numerical Investigation on Instability Flow Behaviors of Liquid Oxygen in a Feeding Pipeline with a Five-Way Spherical Cavity

Computational Modeling of Liquid and Gaseous Control Valves

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