Entropy production by dissipation effects and characteristic vortex evolution in a rocket turbopump DOI Creative Commons
Deyou Li, Jiaqi Zhu, Ruiyi Zhang

et al.

Research Square (Research Square), Journal Year: 2023, Volume and Issue: unknown

Published: June 22, 2023

Abstract The relationship between entropy production and vortex evolution involves the efficiency stability of rotating machinery. This study investigates energy characteristics a rocket turbopump, revealing correlated mechanisms rate using dissipation effects characteristic evolution. Direct turbulent dissipations rigid shear vorticity decomposition methods are utilized to analyze correlation analysis flow loss vorticities in machinery for first time. With an increase rate, hydraulic wall decrease by 60% 38.3%, proportions input (from 13% 8%) remain stable (8%), respectively. local direct (EPDD) inducer-impeller is strongly related entropy, effect total enstrophy on EPDD weaker than that vorticity, indicating suppresses dissipation. significantly static passage turbopump owing weak rotational effect. (EPTD) gradually increases with increasing reaching medium (the maximal degree turbopump) exhibiting rotation loss. Moreover, affects (except diffuser) two reach maximum at designed optimal minimum

Language: Английский

Comparative study on stator corner separation vortex characteristics in axial-flow pump and tubular pump: To understand the effects of guide-vane cone diffusion on horn-like vortices DOI Open Access

Benhong Wang,

F J Wang,

C Y Wang

et al.

Journal of Physics Conference Series, Journal Year: 2024, Volume and Issue: 2707(1), P. 012022 - 012022

Published: Feb. 1, 2024

Abstract The guide-vane cone diffusion is a typical structural difference between an axial-flow pump and tubular pump, which shown as low diffusivity high respectively, but it still unclear how this affects the vortex characteristics in stator corner separation flows. In paper, comparative study of flows was conducted, effects on vortical structures were clarified. Firstly, for apparent features, compared with diffusivity, horn-like has features smaller scale, weaker swirling strength, shorter evolution cycle lower pressure fluctuations. Secondly, dynamics mechanism, can cause additional energy recovery, leads to higher adverse gradients, so easier induce shroud backflow near suction surface. coupled flow field main flow, namely hub backflow, streamwise periodic oscillation function gradient ω S ·▽(▽ p/ρ ) found, induces unique vortex-street-like distributions deformational vorticity rigid R . This physical effect causes mutual competition opposite side. It originating from that greatly suppresses development pump.

Language: Английский

Citations

0

Analysis of the temporal, spatial, and frequency law of the internal flow in a prototype vaned mixed‐flow pump DOI Creative Commons

Chenhan Su,

Jiahao Lu, Ran Tao

et al.

Energy Science & Engineering, Journal Year: 2024, Volume and Issue: 12(7), P. 3088 - 3109

Published: June 17, 2024

Abstract Mixed‐flow pump is a typical using in low‐head cases of water lifting. The flow field pulsation usually an important issue the operation mixed‐flow pumps and their pumping statins. Due to its large size, it difficult monitor internal characteristics well, based on computational fluid dynamics, we use 5678 monitoring points which arranged impeller fixed vane with high tracking network, pressure signals are analyzed by fast Fourier transform variable mode decomposition decompose main frequency intensity signals, then analyze energy dissipation entropy production rate (EPR). It found that there strong low‐frequency (0.416, 0.625, 1.67 Hz) near hub, shroud stronger than hub (at least three times or more); stable (25 generated rotor–stator interference (RSI); EPR can be well combined signal. Reasonably allocating material strength controlling number vanes impellers avoid producing common multiple caused RSI reduce dissipation. Therefore, very effective improving efficiency this part. Under low conditions, siphon outflow passage predict high‐frequency (45.833 attenuation area through phase signal signal, has certain significance for stability efficiency.

Language: Английский

Citations

0

Application and evaluation of dynamic Bradshaw coefficient in shear stress transport turbulence model for hydraulic machinery DOI
Hao Wang, Fujun Wang, C.Y. Wang

et al.

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(7)

Published: July 1, 2024

The Bradshaw assumption, that the ratio of Reynolds shear stress to turbulence kinetic energy (TKE) is a constant roughly equal 0.3, introduced into eddy viscosity and TKE dissipation term transport model (SST). This calibrated by zero-pressure-gradient plate boundary layer test. not applicable rotating separation flows in hydraulic machinery, while its dynamic effects are usually ignored. In this article, comprehensive evaluation coefficient (DBC) SST conducted. First, theoretical analyses existing typical DBCs carried out, suitable expression form driven single number adopted view well-reflected high robustness. According equation structures SST, three strategies proposed, including only introducing DBC (SST-M1), (SST-M2), both (SST-M1 + M2). Second, classical case around hydrofoil employed evaluate application these strategies. results show SST-M1 exhibits severe lift/drag oscillations at large angles attack accompanied fluctuations, indicating poor numerical stability potential risk strategy. contrast, SST-M2 M2 can effectively improve deficiencies overestimating lift underestimating drag attack, which attributed promotion earlier larger flow separation. consistency between two implies plays key role enhancing prediction SST. Therefore, strategy recommended extend applicability for machinery.

Language: Английский

Citations

0

Mitigating surface vortex formation in pump sump intakes through anti-vortex devices: a comprehensive CFD study DOI Creative Commons
Abdulaziz S. Alaboodi, Zahid Hussain, Syed Zaheer Abbas

et al.

Frontiers in Physics, Journal Year: 2024, Volume and Issue: 12

Published: Dec. 5, 2024

The formation of surface vortices in axial pump sumps presents a significant challenge to performance, primarily due the risk impeller cavitation. As such, effective mitigation strategies are imperative. In this study, strength was successfully reduced safe operational level by employing two distinct types anti-vortex devices (AVDs): triangular side fins type (AVDSF) and ring (AVDR). Computational fluid dynamics (CFD) techniques were employed reveal substantial decrease vorticity from 38 s -1 absence AVDs approximately 8 with either AVDSFs or AVDRs, underscoring their remarkable efficacy. Further, helicity, measure vortex twisting, about 0.4 m 2 -2 below 0.1 introduction ring-type AVDs. Detailed analyses velocity streamlines contours elucidated that suppression could be attributed disruption swirl motion induced implementation These findings provide crucial insights into mechanisms underlying suppression, thus paving way for enhanced performance reliability pump’s suction sump applications. is expected prevent cavitation, air ingress, vortex-induced vibrations, resulting more reliable efficient operation industrial settings.

Language: Английский

Citations

0

Entropy production by dissipation effects and characteristic vortex evolution in a rocket turbopump DOI Creative Commons
Deyou Li, Jiaqi Zhu, Ruiyi Zhang

et al.

Research Square (Research Square), Journal Year: 2023, Volume and Issue: unknown

Published: June 22, 2023

Abstract The relationship between entropy production and vortex evolution involves the efficiency stability of rotating machinery. This study investigates energy characteristics a rocket turbopump, revealing correlated mechanisms rate using dissipation effects characteristic evolution. Direct turbulent dissipations rigid shear vorticity decomposition methods are utilized to analyze correlation analysis flow loss vorticities in machinery for first time. With an increase rate, hydraulic wall decrease by 60% 38.3%, proportions input (from 13% 8%) remain stable (8%), respectively. local direct (EPDD) inducer-impeller is strongly related entropy, effect total enstrophy on EPDD weaker than that vorticity, indicating suppresses dissipation. significantly static passage turbopump owing weak rotational effect. (EPTD) gradually increases with increasing reaching medium (the maximal degree turbopump) exhibiting rotation loss. Moreover, affects (except diffuser) two reach maximum at designed optimal minimum

Language: Английский

Citations

0