Thermodynamic Effect on a Cavitating Inducer in Liquid Hydrogen

Goncalves, Éric; Patella, Régiane Fortes; Rolland, Julien; Pouffary, Benoît; Challier, Guillaume

doi:10.1115/1.4002886

Cited by 26 publications

(8 citation statements)

References 14 publications

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“…Such a model was justified by some previous investigators in the studies of both conventional hydraulic machines [13,52], and cryogenic turbomachines [7][8][9], with the cavitation models having been verified by the prese t team of authors in our previous publications [42,44]. The cryogenic hydrofoil flow was simulated and the predicted surface static pressure and temperature were consistent with the test data [53] (Figure 3).…”

Section: Of 21mentioning

confidence: 61%

“…Similar to conventional hydraulic turbomachines of pumps and hydraulic turbines, detrimental cavitation also unavoidably occurs in liquid turbine expanders. Cavitation of conventional hydraulic turbomachines has attracted considerable research, but very limited work on cryogenic turbomachines has been reported [7][8][9].In both conventional hydraulic turbines and pumps, swirling-flow-induced cavitation is significant and detrimental [10][11][12][13][14][15]. In hydraulic turbines, swirling flow originates from the rotating impeller, but further propagates downstream into the diffuser tube, leading to considerable mechanical head dissipations [16].…”

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confidence: 99%

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Cryogenic Cavitation Mitigation in a Liquid Turbine Expander of an Air-Separation Unit through Collaborative Fine-Tuned Optimization of Impeller and Fairing Cone Geometries

Song

Sun

2019

Energies

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An air-separation unit (ASU) uses atmospheric air to produce essential pure gaseous and liquid products for many industrial sectors but requires intensive power consumption. In recent years, cryogenic liquid turbine expanders have been used to replace the traditional J-T valves in air-separation units to save energy. In this paper, an effective design optimization method is proposed to suppress swirling flow and mitigate cavitation in liquid turbines. A flexible tuning of the impeller and fairing cone geometries is simultaneously realized, where the optimization variables are identified via a geometric sensitivity study. A novel objective function is deliberately established by allowing both swirling flow and cavitation characteristics, driving the optimizer to search for deswirling and cavitation-resistant geometries. A kriging surrogate model with an adaptive sampling strategy and a cooperative co-evolution algorithm (CCEA) are incorporated to solve the highly nonlinear optimization problem, where the former reduced the costly evaluations but simultaneously maintained the model prediction accuracy and enabled the aim-oriented global searching (the latter decomposes the problem into several readily solved sub-problems that could be solved in parallel at a high-convergence rate). The optimized impeller and fairing cone geometries were quite favorable for suppressing swirling flow and mitigating cavitation. The impeller cavitation was significantly reduced, with the maximal vapor volume fraction reduced from 0.365 to 0.17 at the blade surface; the diffuser tube high-swirl flow was significantly deswirled and the intensive vapor fraction around the centerline largely reduced, with the maximal vapor volume fraction in the diffuser tube reduced from 0.387 to 0.121. As a result, the isentropic efficiency of the liquid turbine expander was improved from 88.4% to 91.43%. Highlights •Objective function considers both the swirling flow and cavitation characteristics •The developed optimization method is proven to be efficient for cavitating flow mitigation • Collaborative fine-tuned impeller and fairing cone geometries diminish the swirling flow and then suppress cavitation Energies 2020, 13, 50 2 of 21In large-scale internal compression ASUs, high-pressure liquefied air (up to 60-75 MPa) needs to be throttled to a low level (around 0.5-0.6 MPa) so as to meet the technical requirements of the downstream distillation column. Conventionally this has been done with a Joule-Thomson valve, but this can cause severe problems. For example, the high-level pressure head is wasted in the cryogenic ASU, and it unexpectedly raises the cryogenic system temperature, which can compromise the ASU's energy efficiency by 2.5%-3.5%. In recent years, liquid turbine expanders have been adopted in place of traditional Joule-Thomson valves, as they have a proven capacity for enhancing ASU energy efficiency [1][2][3]. Liquid turbine expanders reduce the pressure head of the working medium, while simultaneously converting it into output shaft pow...

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Section: Of 21mentioning

confidence: 61%

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confidence: 99%

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Cryogenic Cavitation Mitigation in a Liquid Turbine Expander of an Air-Separation Unit through Collaborative Fine-Tuned Optimization of Impeller and Fairing Cone Geometries

Song

Sun

2019

Energies

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“…For the simulation of a cavitating flow through a venturi, [1] proposed a sinus barotropic law considering a direct link between the gas volume fraction, phasic densities, local pressure and vapour saturation pressure. For the simulation of cavitating flows in tubopump inducers of spatial rockets, [6] proposed a sinus barotropic law with a vapour saturation pressure calculated from local temperature in the flow. Those robust approaches have provided interesting results for the simulation of hydrofoils [7], venturies [8], turbopump inducers [9,10,11], pumpturbines [12] or fuel injectors [13].…”

Section: Introductionmentioning

confidence: 99%

“…Various authors have attempted to take into account the effect of liquid phase thermal gradients in the flow on cavitation. For barotropic approach [34,6] as well as for inertial controlled growth model [33,35,36], it has been done meanly by calculating the saturated vapour pressure as a function of the local temperature (p sat (T )) and by estimating the bubble temperature variation using energy balance at the bubble scale. In the same time, a few numerical works evoked that vapour production can be driven by thermal controlled growth of vapour bubbles [37,38,39,5].…”

Section: Introductionmentioning

confidence: 99%

On numerical simulation of cavitating flows under thermal regime

Colombet

Silva

Patella

2017

International Journal of Heat and Mass Transfer

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International audienceIn this work, we investigate closure laws for the description of interfacial mass transfer in cavitating flowsunder thermal regime. In a first part, we show that, if bubble resident time in the low pressure area of theflow is larger than the inertial/thermal regime transition time, bubble expansion are no longer monitoredby Rayleigh equation, but by heat transfer in the liquid phase at bubbles surfaces. The modelling of inter-facial heat transfer depends thus on a Nusselt number that is a function of the Jakob number and of thebubble thermal Péclet number. This original approach has the advantage to include the kinetic of phasechange in the description of cavitating flow and thus to link interfacial heat flux to interfacial mass fluxduring vapour production. The behaviour of such a model is evaluated for the case of inviscid cavitatingflow in expansion tubes for water and refrigerant R114 using a four equations mixture model. Comparedwith inertial regime (Rayleigh equation), results obtained considering thermal regime seem to predictlower local gas volume fraction maxima as well as lower gradients of velocity and gas volume fraction.It is observed that global vapour production is closely monitored by volumetric interfacial area (bubblesize and gas volume fraction) and mainly by the Jakob number variations. It is found that, in contrast withphase change occurring in common boiling flow, Jakob number variation is influenced by phasic temper-ature difference but also by density ratio variation with pressure and temperature

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Numerical Simulation of Cavitating Flows with Different Cavitation and Turbulence Models

Goncalves

2017

Cavitation Instabilities and Rotordynamic Effects in Turbopumps and Hydroturbines

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Thermodynamic Effect on a Cavitating Inducer in Liquid Hydrogen

Abstract: International audienc

Cited by 26 publications

References 14 publications

Cryogenic Cavitation Mitigation in a Liquid Turbine Expander of an Air-Separation Unit through Collaborative Fine-Tuned Optimization of Impeller and Fairing Cone Geometries

Cryogenic Cavitation Mitigation in a Liquid Turbine Expander of an Air-Separation Unit through Collaborative Fine-Tuned Optimization of Impeller and Fairing Cone Geometries

On numerical simulation of cavitating flows under thermal regime

Numerical Simulation of Cavitating Flows with Different Cavitation and Turbulence Models

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