Combined experimental and computational investigation of cavitation evolution and excited pressure fluctuation in a convergent–divergent channel

Chen, Guanghao; Wang, Guoyu; Hu, Cheng; Huang, Biao; Gao, Yuan; Zhang, Mindi

doi:10.1016/j.ijmultiphaseflow.2015.02.007

Cited by 54 publications

(21 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1(a). The simultaneous sampling system [23] which synchronizes the 4 pressure transducers and high-speed camera by a controller, are shown in Fig. 1(b).…”

Section: Experiments Setupmentioning

confidence: 99%

Investigation of Unsteady Sheet/Cloud Cavitation in the Divergent Section of a Nozzle With Emphasis on the Mechanism of Shock Wave Propagation

Xiaobo¹,

Cheng²,

Wang³

et al. 2017

Computational and Experimental Methods in Multiphase and Complex Flow IX

Self Cite

View full text Add to dashboard Cite

The objective of this paper is to investigate the unsteady pressure fluctuation characteristics in the process of breakup, and shedding of unsteady sheet/cloud cavitating flows via combined experimental and computational methods. Experiments are conducted in the divergent section of a convergentdivergent channel using a simultaneous sampling technique to synchronize the transient cavitation behaviours and wall-pressure signals. In the numerical simulations, the Zwart cavitation model and the modified RNG k-ε turbulence model are solved, with the compressibility effects of both water and vapour considered. In addition, one-dimensional bubbly shock wave relationship is applied to analyse the process of the discontinuity propagation. Two different types of cavity breakup and shedding existing in the unsteady sheet/cloud cavitating flows are observed, which is induced by re-entrant flow and discontinuity propagation, respectively. The re-entrant flow generates at the rear of the cavity, moving forward along the wall. When it arrives at the throat, it breaks up the attached cavity, resulting in the cloud cavity shedding. During the process, the wall-pressure fluctuation is relatively small. The discontinuity propagation results from the bubbly shock in water/vapour mixture of the sheet/cloud cavity. There is a significant difference in vapour fraction across the discontinuity. The pre-discontinuity area is almost pure vapour, and the post-discontinuity area consists of water/vapour mixtures with relatively low vapour fraction. During the discontinuity propagation, the pressure peak exists at shock wave front. When the discontinuity arrives at the throat, the void fraction will suddenly decrease, which indicates the low vapour generation rate. Under the convection of the main flow, the attached cavity will be separated from the newly generated vapour, resulting in the attached cavity breaking up and being shed.

show abstract

“…1(a). The simultaneous sampling system [23] which synchronizes the 4 pressure transducers and high-speed camera by a controller, are shown in Fig. 1(b).…”

Section: Experiments Setupmentioning

confidence: 99%

Investigation of Unsteady Sheet/Cloud Cavitation in the Divergent Section of a Nozzle With Emphasis on the Mechanism of Shock Wave Propagation

Xiaobo¹,

Cheng²,

Wang³

et al. 2017

Computational and Experimental Methods in Multiphase and Complex Flow IX

Self Cite

View full text Add to dashboard Cite

show abstract

“…20 A data acquisition board is used to transform the output of transducers into digital values; according to the focus of the investigation, 1.024 MHz is chosen in this study.…”

Section: Approach and Setupmentioning

confidence: 99%

Experimental study on the influence of air injection on unsteady cloud cavitating flow dynamics

Zhang

Zhao

Wei

et al. 2016

Advances in Mechanical Engineering

Self Cite

View full text Add to dashboard Cite

The main purpose of this study was to investigate the influence of air-injection technique on unsteady cloud cavitating flow dynamics. High-speed camera and pressure measurement system are used to record ventilated cavitation images and wall-pressure fluctuation in a convergent-divergent channel, respectively. The measured ventilated cavitation evolution process and corresponding wall-pressure fluctuation are compared with those obtained under non-ventilation condition. The results show that air-injection technique can significantly suppress pressure pulses induced by cavity collapse. Furthermore, by increasing ventilation rate, the time evolution of cavitation tends to be more stable, the wall-pressure fluctuation magnitude is reduced significantly, and the cloud shedding frequency is reduced, which is believed to be related to the interaction between injected air and re-entrant flow.

show abstract

“…On the contrary, pressure fluctuations were unavoidably induced by the cavitation because of the growth and the collapse of the cavitated bubbles [15][16][17]. The experimental study captured significant quasi-periodic pressure fluctuations in the cavitation region when the sheet/cloud cavitation occurred [18]. Moreover, Yutaka Ito et al observed the periodical shedding of the liquid nitrogen (LN 2 ) cavitation cloud over a plano-convex hydrofoil and a bluff body [19].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Effects of Injection Fluctuations on Liquid Nitrogen Spray Cooling

et al. 2019

View full text Add to dashboard Cite

Spray cooling with liquid nitrogen is increasingly utilized as an efficient approach to achieve cryogenic cooling. Effects of injection mass flow rate fluctuations on the evaporation, temperature distribution, and droplet distribution of a spray field were examined by employing a validated Computational Fluid Dynamics (CFD) numerical model. The numerical results indicated that injection fluctuations enhanced the volume-averaging turbulent kinetic energy and promoted the evaporation of the whole spray field. The strengthened mass and heat transfer between the liquid nitrogen droplets and the surrounding vapor created by the fluctuating injection led to a lower temperature of the whole volume. A relatively smaller droplet size and a more inhomogeneous droplet distribution were obtained under the unsteady inlet. The changes of the frequency and the amplitude of the fluctuations had little effects on the overall spray development. The results could enrich the knowledge of the relation between the inevitable fluctuations and the overall spray development and the cooling performance in a practical spray cooling system with cryogenic fluids.

show abstract

Combined experimental and computational investigation of cavitation evolution and excited pressure fluctuation in a convergent–divergent channel

Cited by 54 publications

References 30 publications

Investigation of Unsteady Sheet/Cloud Cavitation in the Divergent Section of a Nozzle With Emphasis on the Mechanism of Shock Wave Propagation

Investigation of Unsteady Sheet/Cloud Cavitation in the Divergent Section of a Nozzle With Emphasis on the Mechanism of Shock Wave Propagation

Experimental study on the influence of air injection on unsteady cloud cavitating flow dynamics

Numerical Study of the Effects of Injection Fluctuations on Liquid Nitrogen Spray Cooling

Contact Info

Product

Resources

About