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Journal articles on the topic 'Valves. Cavitation'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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Lu, L., J. Zou, X. Fu, et al. "Cavitating flow in non-circular opening spool valves with U-grooves." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 10 (2009): 2297–307. http://dx.doi.org/10.1243/09544062jmes1504.

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Cavitating flow in non-circular opening spool valves with U-grooves has been investigated in this article. Multifarious cavitating properties, including acoustic cavitation, morphologic cavitation, and discharge performance with cavitation, are investigated, the correlations of which are discussed. The critical opening condition in each valve is obtained based on the analysis of a throttling model. It is found that the cavitating properties show remarkable differences in the two situations when the opening is larger and smaller than the critical opening. Additionally, cavitation impacts on the discharge performance are investigated with the assistance of acoustic and visual detection.

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Yi, Dayun, Liang Lu, Jun Zou, and Xin Fu. "Interactions between poppet vibration and cavitation in relief valve." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 8 (2014): 1447–61. http://dx.doi.org/10.1177/0954406214544304.

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Poppet vibration and cavitation, two representative phenomena in relief valves, are considered as the roots of the violent noise, erosion, and structure damage. In this paper, the interactions between the poppet vibration characteristics and cavitation property in relief valves with the unconfined poppet are investigated experimentally. Tests have been performed in stable and unstable valves under cavitation and noncavitation conditions. The valve housing is fabricated by Perspex for flow visualization. As for the influence of cavitation on vibration characteristics, it is found that the generated cavitation bubbles in the downstream circuit decrease the flow coefficient and fluid viscosity, and decrease the hydrodynamic spring in turn. The location of cavitating flow, characterized by the low local pressure, changes the thrust on poppet and poppet lift, affecting the radial stiffnesses of mechanical spring and hydrodynamic spring, respectively. On the other hand, as for the influence of vibration on cavitation property, it is found that the poppet vibration leads to a dramatic increase of the noise comparing to the fixed poppet conditions. Spectrum analysis shows that augmented noise in unstable valves mainly comes from the intensification of cavitation noise. A reason for this is that the vibration of poppet leads to a quick and violent collapse of large amount of cavities developed from the throttling region, which should be performed as attached cavities and avoided from collapse in the stable poppet conditions.

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Li, Jun-ye, Zhi-xin Gao, Hui Wu, and Zhi-jiang Jin. "Numerical Investigation of Methodologies for Cavitation Suppression Inside Globe Valves." Applied Sciences 10, no. 16 (2020): 5541. http://dx.doi.org/10.3390/app10165541.

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Cavitation inside globe valves, which is a common phenomenon if there is a high-pressure drop, is numerically investigated in this study. Firstly, the cavitation phenomenon in globe valves with a different number of cages is compared. When there is no valve cage, cavitation mainly appears at the valve seat, the bottom of the valve core, and the downstream pipelines. By installing a valve cage, cavitation bubbles can be restricted around the valve cage protecting the valve body from being damaged. Secondly, the effects of the outlet pressure, the working temperature, and the installation angle of two valve cages in a two-cage globe valve are studied to find out the best method to suppress cavitation, and cavitation number is utilized to evaluate cavitation intensity. Results show that cavitation intensity inside globe valves can be reduced by increasing the valve outlet pressure, decreasing the working temperature, or increasing the installation angle. Results suggest that increasing the outlet pressure is the most efficient way to suppress cavitation intensity in a globe valve, and the working temperature has a minimal effect on cavitation intensity.

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Bikai, Zhu, Huang Yan, Zhang Tiehua, and Li Zhuangyun. "Experimental investigation of the flow characteristics of small orifices and valves in water hydraulics." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 216, no. 4 (2002): 235–45. http://dx.doi.org/10.1243/095440802321194512.

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This paper describes an experimental investigation of the flow characteristics of water passing through small sharp-edged cylindrical orifices and valves of different shapes in water hydraulics. The test results using orifices with aspect ratios, l/d, of 1–15 and diameters of 0.8-3 mm show that the flow coefficients in the case of non-cavitating flow are larger than those of flow with cavitation and decrease with increase in the aspect ratio. However, the flow coefficients of flow with cavitation tend to be of constant value close to the contraction coefficient, Cc at small aspect ratios. Orifices with large aspect ratios have the effect of suppressing cavitation. Experimental results concerning the spool valve illustrate that the sharp-edged valve is less cavitation stricken at large opening than at small opening. Throttles with a triangular notch have better anticavitation ability than those with a square notch. The flow of the throttle with a square notch is significantly affected by the flow direction and the shape of the flow passage.

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Li, Yan Jie, Yun Feng Bai, Jian Zhang, and Ji Hai Jiang. "Flow Field Simulation and Experimental Research on the Triangle Groove Cone Throttle Valve." Applied Mechanics and Materials 779 (July 2015): 42–49. http://dx.doi.org/10.4028/www.scientific.net/amm.779.42.

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Aiming at the problems of cavitation noise in the cone throttle valve, triangle groove cone throttle valves with 45, 53, 60 degree were selected as the research objects. Firstly the structure characteristics of the throttle valves were analyzed, then the three-dimensional models and mathematical models were established. By using the finite element simulation software ADINA, the simulation diagrams about pressure and flow velocity of the cone valves were obtained and then verified on the test bench which was about the noise characteristics of throttle valve. The investigation result showed that the flow field of the cone valve was complex, and there were local low pressure areas where were high incidence of cavitation; the valve with 60 degree spool had the minimum noise, which showed the best performance, then the 53 degree spool was a bit poor, and the worst valve was 45 degree spool. Increasing the angles of the triangle groove appropriately could reduce the cavitation noise and improve the performance of the valve. This investigation has great significance on understanding the flow field and controlling the cavitation noise in triangle groove cone throttle valves. Besides it also has a certain reference value to other hydraulic components on the cavitation noise control and structural optimization.

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Lee, C. S., K. B. Chandran, and L. D. Chen. "Cavitation Dynamics of Medtronic Hall Mechanical Heart Valve Prosthesis: Fluid Squeezing Effect." Journal of Biomechanical Engineering 118, no. 1 (1996): 97–105. http://dx.doi.org/10.1115/1.2795951.

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The cause of cavitation in mechanical heart valves is investigated with Medtronic Hall tilting disk valves in an in vitro flow system simulating the closing event in the mitral position. Recordings of pressure wave forms and photographs in the vicinity of the inflow surface of the valve are attempted under controlled transvalvular loading rates averaged during valve closing period. The results revealed presence of a local flow field with a very high velocity around the seat stop of mechanical heart valves that could induce pressure reduction below liquid vapor pressure and a cloud of cavitation bubbles. The analysis of the results indicates that the “fluid squeezing” between the stop and occluder as the main cause of cavitation in Medtronic Hall valves. The threshold loading rate for cavitation initiation around the stop was found to be very low (300 and 400 mmHg/s; half the predicted normal human loading rate that was estimated to be 750 mmHg/s) because even a mild impact created a high speed local flow field on the occluder surface that could induce pressure reduction below vapor pressure. The present study suggests that mechanical heart valves with stops at the edge of major orifice region are more vulnerable to cavitation, and hence, have higher potential for damage on valve components and formed elements in blood.

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Qian, Jin-yuan, Zhi-xin Gao, Cong-wei Hou, and Zhi-jiang Jin. "A comprehensive review of cavitation in valves: mechanical heart valves and control valves." Bio-Design and Manufacturing 2, no. 2 (2019): 119–36. http://dx.doi.org/10.1007/s42242-019-00040-z.

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Yusof, N. S. B., Azmin Shakrine Mohd Rafie, M. K. A. Ariffin, and N. Othman. "Computational Analysis of the Groove Effect to Reduce the Cavitation in Ball Valves." Applied Mechanics and Materials 629 (October 2014): 414–19. http://dx.doi.org/10.4028/www.scientific.net/amm.629.414.

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Cavitation is a phenomenon that frequently creates fear within the engineering industry as the violent and critical attacks by cavitation can cause a lot of damage to ball valves. This paper is presented to reduce the risk of cavitation attack due to dramatic pressure drop and to demonstrate the ball valve performance. The ball valve with grooves was simulated and compared with current method under same boundary conditions as with existing experimental of ball valves. The proposed device can be operated in aircraft to isolate the fuel system and the engine fuel system after engine shutdown or emergency. The proposed implementation has successfully shown to eliminate the dramatic pressure drop effects to the ball valve. In the case study, at a closing angle of 40° at which violent cavitation occurs, the ball valve showed increasing cavitation intensity performance to 0.3 or 30%. The average performance of the cavitation index for all cases also increased to 24%.

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Zhang, Jian. "Flow characteristics of a hydraulic cone-throttle valve during cavitation." Industrial Lubrication and Tribology 71, no. 10 (2019): 1186–93. http://dx.doi.org/10.1108/ilt-10-2018-0394.

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Purpose This paper aims to resolve the cavitation problem encountered in cone throttle valves concerning fluid flow performance and pitting from cavitation luminescence, the author studied the flow field within a cone throttle valve set with various valve openings, inlet pressures and outlet back pressures. Design/methodology/approach The flow and cavitation distribution in the valve under different pressure conditions were obtained in simulations. To confirm these results experimentally, a hydraulic cavitation platform was constructed. The valve was made of polymethyl methacrylate material with high transparency to observe the cavitation directly, as well as cavitation luminescence. The flow characteristics of this valve were measured under various working conditions. Findings With increasing cavitation strength, a reduction in cavitation on the throttle capacity was more evident. Increasing the back pressure and reducing the working pressure of the valve appropriately improves the flow capacity of the valve, which subsequently improves the performance of the valve. The cavitation luminescence is also linearly related to cavitation intensity. That is, the stronger the flow capacity of the valve, the less likely the luminescence is produced. Moreover, a stronger luminescence intensity worsens the flow performance of the valve. Research limitations/implications Owing to the limitation of experimental means and lack of research on bubble shape, the subsequent research will complement this aspect. Practical implications With a view to providing theoretical and experimental support, cavitation luminescence is also studied to gain a deeper understanding of the cavitation mechanism in hydraulic valves. Originality/value The innovation of this paper is to study the cavitation luminescence in the hydraulic system.

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Qiu, Chang, Cheng-Hang Jiang, Han Zhang, Jia-Yi Wu, and Zhi-Jiang Jin. "Pressure Drop and Cavitation Analysis on Sleeve Regulating Valve." Processes 7, no. 11 (2019): 829. http://dx.doi.org/10.3390/pr7110829.

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The sleeve regulating valve is widely used in the pipeline systems of process industries to control fluid flow. When flowing through the sleeve regulating valve, the water is easy to reach cavitation because of the pressure drop in the partial region, which may cause serious damage to pipeline system. In this paper, the pressure drop and cavitation characteristics in the sleeve regulating valve for different pressure differences and valve core displacements are investigated using a multiphase cavitation model. The pressure drop, velocity and vapor volume distribution in the regulating valves are obtained and analyzed. The total vapor volumes are also predicted and compared. The results show that the decrease of the valve core displacement induces the enlargement of the vapor distribution region and the increase of the vapor density. The increase of the pressure difference induces a more serious cavitation. The pressure difference has a slight influence on the cavitation intensity and density in the regulating valve when the valve core displacement is 60 mm. With the decrease of the valve core displacement, the effects of the pressure difference on the cavitation intensity are enhanced. This work is of significance for the cavitation control of the sleeve regulating valves.

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LI, BEIBEI, WENHUA LI, MINGLI JIAO, BINGYANG WANG, and XIUMEI LIU. "ANALYSIS OF CAVITATION CHARACTERISTICS IN THROTTLE VALVE WITH DIFFERENT STRUCTURE PARAMETERS." Journal of Mechanics in Medicine and Biology 17, no. 03 (2016): 1750047. http://dx.doi.org/10.1142/s0219519417500476.

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The pressure and cavitation characteristics of fluid through throttle valves with different structure parameters were investigated numerically using computational fluid dynamics. The mass flow rate, pressure drop, and the volume fraction of the vapor in the single and two-step throttle valve were computed. The cavitation regions were mainly distributed on the top of the valve rod and the corner of the valve seat in both of the different throttle valves. The size of cavitation region at the corner of the channel grows firstly, and then decrease with the decreasing opening degree. Furthermore, the lowest pressure region, as well as the area and strength of cavitation region, in the two-step throttle valve were smaller than a single one at the same opening degree. The formula for equivalent orifice area of throttle valve was derived, in order to explain the effect of opening degree. The results indicated that the two-step throttle has high anti-cavitation capability.

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Bernad, Sandor I., and Romeo Susan-Resiga. "Numerical Model for Cavitational Flow in Hydraulic Poppet Valves." Modelling and Simulation in Engineering 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/742162.

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The paper presents a numerical simulation and analysis of the flow inside a poppet valve. First, the single-phase (liquid) flow is investigated, and an original model is introduced for quantitatively describing the vortex flow. Since an atmospheric outlet pressure produces large negative absolute pressure regions, a two-phase (cavitating) flow analysis is also performed. Both pressure and density distributions inside the cavity are presented, and a comparison with the liquid flow results is performed. It is found that if one defines the cavity radius such that up to this radius the pressure is no larger than the vaporization pressure, then both liquid and cavitating flow models predict the cavity extent. The current effort is based on the application of the recently developed full cavitation model that utilizes the modified Rayleigh-Plesset equations for bubble dynamics.

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Johansen, Peter, Keefe B. Manning, John M. Tarbell, Arnold A. Fontaine, Steven Deutsch, and Hans Nygaard. "A New Method for Evaluation of Cavitation Near Mechanical Heart Valves." Journal of Biomechanical Engineering 125, no. 5 (2003): 663–70. http://dx.doi.org/10.1115/1.1613297.

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Evaluation of cavitation in vivo is often based on recordings of high-pass filtered random high-frequency pressure fluctuations. We hypothesized that cavitation signal components are more appropriately assessed by a new method for extraction of random signal components of the pressure signals. We investigated three different valve types and found a high correlation between the two methods r2:0.8806−0.9887. The new method showed that the cavitation signal could be extracted without a priori knowledge needed for setting the high-pass filter cut off frequency, nor did it introduce bandwidth limitation of the cavitation signal.

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OSHIMA, Shigeru. "Cavitation and Characteristics of Spherical Poppet Valves." Hydraulics & Pneumatics 23, no. 3 (1992): 302–8. http://dx.doi.org/10.5739/jfps1970.23.302.

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Qian, Jin-yuan, Zhi-xin Gao, Wen-qing Li, and Zhi-jiang Jin. "Cavitation Suppression of Bileaflet Mechanical Heart Valves." Cardiovascular Engineering and Technology 11, no. 6 (2020): 783–94. http://dx.doi.org/10.1007/s13239-020-00484-w.

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Herbertson, Luke H., Varun Reddy, Keefe B. Manning, Joseph P. Welz, Arnold A. Fontaine, and Steven Deutsch. "Wavelet Transforms in the Analysis of Mechanical Heart Valve Cavitation." Journal of Biomechanical Engineering 128, no. 2 (2005): 217–22. http://dx.doi.org/10.1115/1.2165694.

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Cavitation is known to cause blood element damage and may introduce gaseous emboli into the cerebral circulation, increasing the patient’s risk of stroke. Discovering methods to reduce the intensity of cavitation induced by mechanical heart valves (MHVs) has long been an area of interest. A novel approach for analyzing MHV cavitation is presented. A wavelet denoising method is explored because currently used analytical techniques fail to suitably unmask the cavitation signal from other valve closing sounds and noise detected with a hydrophone. Wavelet functions are used to denoise the cavitation signal during MHV closure and rebound. The wavelet technique is applied to the signal produced by closure of a 29-mm Medtronic-Hall MHV in degassed water with a gas content of 5ppm. Valve closing dynamics are investigated under loading conditions of 500, 2500, and 4500mmHg∕s. The results display a marked improvement in the quantity and quality of information that can be extracted from acoustic cavitation signals using the wavelet technique compared to conventional analytical techniques. Time and frequency data indicate the likelihood and characteristics of cavitation formation under specified conditions. Using this wavelet technique we observe an improved signal-to-noise ratio, an enhanced time-dependent aspect, and the potential to minimize valve closing sounds, which disguise individual cavitation events. The overall goal of this work is to eventually link specific valves with characteristic waveforms or distinct types of cavitation, thus promoting improved valve designs.

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Zapanta, Conrad M., Edward G. Liszka, Theodore C. Lamson, et al. "A Method for Real-Time In Vitro Observation of Cavitation on Prosthetic Heart Valves." Journal of Biomechanical Engineering 116, no. 4 (1994): 460–68. http://dx.doi.org/10.1115/1.2895797.

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A method for real-time in vitro observation of cavitation on a prosthetic heart valve has been developed. Cavitation of four blood analog fluids (distilled water, aqueous glycerin, aqueous polyacrylamide, and aqueous xanthan gum) has been documented for a Medtronic/Hall™ prosthetic heart valve. This method employed a Penn State Electrical Ventricular Assist Device in a mock circulatory loop that was operated in a partial filling mode associated with reduced atrial filling pressure. The observations were made on a valve that was located in the mitral position, with the cavitation occurring on the inlet side after valve closure on every cycle. Stroboscopic videography was used to document the cavity life cycle. Bubble cavitation was observed on the valve occluder face. Vortex cavitation was observed at two locations in the vicinity of the valve occluder and housing. For each fluid, cavity growth and collapse occurred in less than one millisecond, which provides strong evidence that the cavitation is vaporous rather than gaseous. The cavity duration time was found to decrease with increasing atrial pressure at constant aortic pressure and beat rate. The area of cavitation was found to decrease with increasing delay time at a constant aortic pressure, atrial pressure, and beat rate. Cavitation was found to occur in each of the fluids, with the most cavitation seen in the Newtonian fluids (distilled water and aqueous glycerin).

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Jia, Tian Chi, Zhang Yong Wu, Juan Wang, Ru Guang Feng, and Yan Jin Qin. "Design and Performance Analysis of Digital Pressure Relief Valve of Water-Based Hydraulic." Applied Mechanics and Materials 387 (August 2013): 369–73. http://dx.doi.org/10.4028/www.scientific.net/amm.387.369.

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this paper use the stepper motor as driver, designed the structure of a digital pressure relief valve of water-based hydraulic, and establishment mathematical model of the valve element cavitation flow field, simulated and analyzed the different the valve element cavity volume and rounded of water pressure relief valves cavitation flow field by use Fluent software. The results showed that: It can suppressed cavitation that appropriate increases cavity volume and reduced the spool fillet.

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Li, Wen-qing, Zhi-xin Gao, Zhi-jiang Jin, and Jin-yuan Qian. "Transient Study of Flow and Cavitation Inside a Bileaflet Mechanical Heart Valve." Applied Sciences 10, no. 7 (2020): 2548. http://dx.doi.org/10.3390/app10072548.

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A mechanical heart valve (MHV) is an effective device to cure heart disease, which has the advantage of long life and high reliability. Due to the hemodynamic characteristics of blood, mechanical heart valves can lead to potential complications such as hemolysis, which have damage to the blood elements and thrombosis. In this paper, flowing features of the blood in the valve are analyzed and the cavitation mechanism in bileaflet mechanical heart valve (BMHV) is studied. Results show that the water hammer effect and the high-speed leakage flow effect are the primary causes of the cavitation in the valve. Compared with the high-speed leakage flow effect, the water hammer has a greater effect on the cavitation strength. The valve goes through four kinds of working condition within one heart beating period, including, fully opening stage, closing stage and fully closing stage. These four stages, respectively, make up 8.5%, 16.1%, 4.7% and 70.7% of the total period. The cavitation occurs on the fully closing stage. When the valve is in closing stage, the high pressure downstream of the valve lasts for about 20 ms and the high-speed leakage flow lasts for about 200 ms. This study systematically analyzes the causes of cavitation emerged in the process of periodic motion, which proposes the method for characterizing the intensity of the cavitation, and can be referred to for the cavitation suppression of the BHMV and similar valves.

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Clarke, Brad, and Kari Oksanen. "Taking the mystery out of cavitation piloted valves." World Pumps 2015, no. 9 (2015): 34–41. http://dx.doi.org/10.1016/s0262-1762(15)30240-6.

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Oshima, Shigeru, Timo Leino, Matti Linjama, Kari Tapio Koskinen, and Matti Juhani Vilenius. "Effect of Cavitation in Water Hydraulic Poppet Valves." International Journal of Fluid Power 2, no. 3 (2001): 05–13. http://dx.doi.org/10.1080/14399776.2001.10781115.

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Požar, Tomaž, Žan Pirc, Egon Susič, and Rok Petkovšek. "Simplified detection of cavitation threshold in control valves." Applied Acoustics 165 (August 2020): 107320. http://dx.doi.org/10.1016/j.apacoust.2020.107320.

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Lee, Hwansung, and Yoshiyuki Taenaka. "Mechanism for cavitation phenomenon in mechanical heart valves." Journal of Mechanical Science and Technology 20, no. 8 (2006): 1118–24. http://dx.doi.org/10.1007/bf02916011.

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Zuti, Zhang, Cao Shuping, Luo Xiaohui, Shi Weijie, and Zhu Yuquan. "New approach of suppressing cavitation in water hydraulic components." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 21 (2016): 4022–34. http://dx.doi.org/10.1177/0954406216657847.

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Cavitation frequently appears in high pressure water hydraulic components and leads to serious hydraulic erosions and horrible hydrodynamic noises. In this paper, a novel approach of suppressing cavitation was proposed, inducing the outlet pressure back to the orifice to improve the pressure distribution of throttle valves. In order to realize this approach, an optimized throttle valve chamber structure was designed. After that, the anticavitation performance of the valve was investigated. A theoretical cavitation cloud model was built based on bubble dynamics. In order to solve the mathematic cavitation model, the velocity field and pressure distribution of the novel throttle valve were simulated through Computational Fluid Dynamics(CFD). Combining the simulation results, the mathematic cavitation cloud model was solved through numerical calculations. Moreover, new indexes estimating cavitation intensity were proposed scientifically to investigate cavitation phenomenon. Then, the comparison of the novel throttle valve (with an innovative valve chamber) and traditional throttle valve in anticavitation performance was conducted under different conditions. Finally, the experiment about anticavitation performance was completed on the test rig. The calculation and experiment results indicated that the approach, inducing the outlet pressure back to the orifice, was effective in suppressing cavitation.

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Ren, Hao Ling, Tian Liang Lin, Cheng Miao, Zhong Shen Li, and Sheng Jie Fu. "Analysis of the Cavitation in the Jet Flow Field of the V-Type Valve Orifice." Applied Mechanics and Materials 779 (July 2015): 55–61. http://dx.doi.org/10.4028/www.scientific.net/amm.779.55.

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Valve orifice is the common place that the cavitation easily occurs in the hydraulic systems. This paper introduces a criteria to estimate the inception of the cavitation of the V-type valve orifice with the stress state. Based on this criteria, a cavitation model which considers the dynamics of the cavity and incompressible gas is proposed to analyze the pressure, stress and the cavitation distribution of the phase in the V-type orifice. The distributions of the cavitation along the axis and the cross section are analyzed. The simulation results show that the cavitation is easily occurred in the downstream just after the orifice and the bubbles are mostly gathered in the top of the cross section which is vertical to the axis of the flow field. The simulation results is reasonable according to the facts. Accordingly, the cavitation of the V-type orifice is predicted reasonably. The research and results of this paper are useful for the design of the hydraulic valves.

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BYEON, SUN SEOK, SANG JUN LEE, and YOUN-JEA KIM. "NUMERICAL STUDY ON THE INHIBITION OF CAVITATION IN PIPING SYSTEMS." International Journal of Modern Physics: Conference Series 19 (January 2012): 374–80. http://dx.doi.org/10.1142/s2010194512008963.

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Abrupt closing valve in piping systems is sometimes resulted in cavitation due to the occurrence of high pressure difference. The bubbles generating by cavitation influence operating pressure and then those generate shock wave and vibration. These phenomena can consequentially cause to corrosion and erosion. So, the cavitation is the important factor to consider reliability of piping systems and mechanical lifetime. This paper investigated the various inhibition methods of cavitation in piping systems in which butterfly valves are installed. To prevent cavitation occurrence, it is desirable to analyze its characteristics between the upstream and downstream of process valve. Results show that the fluid velocity is fast when a working fluid passed through butterfly valve. The pressure of these areas was not only under saturation vapor pressure of water, but also cavitation was continuously occurred. We confirmed that the effect of existence of inserted orifice and influence to break condition under saturation vapor pressure of water. Results were graphically depicted by pressure distribution, velocity distribution, and vapor volume fraction.

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Li, Shu Xun, Qiang Wei Ding, Xiao Gang Xu, and Yi Lin Fan. "Study on Internal Parameters of Cage-Type Trim of Multi-Stage Depressurization Steam Trap." Advanced Materials Research 945-949 (June 2014): 964–67. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.964.

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Aiming at the lack of research for key parameters of the cage-type trim of sleeve-type steam trap, the numerical simulation calculation was carried out for the cavitation flow in valve, the influences of orifice types, orifice diameter, guide sleeve types on cavitation were researched. The distribution of pressure, velocity and vapor volume fraction on flow field were got for different sleeve parameters. The results show that using multi-stage sleeve, and decreasing the orifice diameter properly can suppress the occurrence and development of cavitation, and the double orifices structure sleeve is more favorable to anti-cavitation, the gap sleeve is superior to the guide sleeve. It can provide certain references for the research of anti-cavitation and multi-stage depressurization valves.

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Xiumei, Liu, He Jie, Li Beibei, et al. "Study on Unsteady Cavitation Flow and Pressure Pulsation Characteristics in the Regulating Valve." Shock and Vibration 2021 (January 16, 2021): 1–10. http://dx.doi.org/10.1155/2021/6620087.

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A combined numerical-experiment investigation on the unsteady cavitation flow and pressure fluctuation characteristics in the regulating valves is conducted in this paper. The cavitation flow in the regulating valve is an unsteady and periodic flow which could be divided into fixed and travelling cavitation bubbles. The fixed cavitation bubbles are formed in the gap in the initial stage and then fell off and formed the travelling cavitation bubbles because of the re-entrant jet. The travelling cavitation bubbles move downstream, oscillate, and break up into several smaller bubbles. Changes in the length/radius ratio (L/R0) of the valve spool is an important factor affecting unsteady cavitation flow and pressure pulsation characteristics in the regulating valve. The length of travelling cavitation bubbles increases firstly and then decreases with increasing time. With the increase of the length/radius ratio (L/R0), the oscillation period of cavitation bubbles also increases. In the initial stage of cavitation bubbles, the velocity distribution inside the regulating valve is relatively stable, and no re-entrant jet could be found although L/R0 is different. In the collapse stage of cavitation bubbles, the velocity distribution becomes extremely unstable because the collapsing cavitation bubbles affect the pressure drop and velocity field in the flow channel. Furthermore, the amplitude of pressure pulsation increases gradually, and the peak time of the pressure pulsation is gradually delayed while increasing the length/diameter ratio.

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Kapranova, A. B., A. E. Lebedev, A. M. Melzer, and S. V. Neklyudov. "The behavior of a gas–vapor system inside a cavitation bubble during axial valve operation." Vestnik IGEU, no. 3 (June 30, 2020): 58–64. http://dx.doi.org/10.17588/2072-2672.2020.3.058-064.

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The energy industry needs reliable, environmentally friendly control valves, which include the category of control valves. The creation of conditions for reducing the intensity of cavitation effects at the initial stages of its development determines the main purpose of the study which aims to prevent possible negative consequences of developed cavitation, which in their turn include erosion of the flowing surfaces of the elements of the specified equipment and vibrations that go beyond operating standards. One of the possible ways to solve the problem is to use the process of throttling fluid flows in the working volume of the control device. The particular interest is paid to the mathematical description of the mechanism of formation of cavitation bubbles in terms of gas–vapor system. To obtain analytical results for describing the behavior of the gas–vapor system of the macro-system of cavitation bubbles, we used the authoring stochastic model of the cavitation bubbles formation process in the flow part of the axial valve. The model was constructed on the basis of the energy method in the framework of the equilibrium representation of states of an energetically closed macro-system. The dependence of the random component of the angular momentum of the cavitation bubble on the flow coefficient of the valve and the conditional diameter of its flow cross section for various ratios of gas and vapor concentration inside the bubbles has been analysed. The implementation of the process of throttling fluid flows in the control valve using the proposed design solution to the separator–external locking shell allows reducing the random component of the angular momentum of the cavitation bubble and increasing the valve throughput coefficient at various stages of the separator opening.

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Vriz, Olga, Fatma Arshi, Mawada Ahmed, et al. "Cavitation phenomenon in mechanical prosthetic valves: Not only microbubbles." Echocardiography 37, no. 6 (2020): 876–82. http://dx.doi.org/10.1111/echo.14692.

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Gao, H., W. Lin, and T. Tsukiji. "Investigation of Cavitation Near the Orifice of Hydraulic Valves." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 220, no. 4 (2006): 253–65. http://dx.doi.org/10.1243/09544100jaero26.

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Rahmeyer, William J. "Test Procedures for Determining Cavitation limits in Control Valves." Journal - American Water Works Association 78, no. 11 (1986): 55–58. http://dx.doi.org/10.1002/j.1551-8833.1986.tb05848.x.

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Lo, Chi-Wen, Jia-Shing Liu, Po-Chien Lu, and Ned H. Hwang. "CAVITATION BEHAVIOR OF THREE MONOLEAFLET VALVES UNDER ACCELERATED TESTING." ASAIO Journal 52, no. 2 (2006): 1A. http://dx.doi.org/10.1097/00002480-200603000-00021.

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TANI, Kiyohito, Yukio ITO, Risaburo OBA, Shinichi MIYAZAKI, and Naotake SHIMIZU. "A Trial to Reduce Cavitation Noises in Control Valves." Transactions of the Japan Society of Mechanical Engineers Series B 58, no. 546 (1992): 327–30. http://dx.doi.org/10.1299/kikaib.58.327.

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ZAPANTA, CONRAD M., DAVID R. STINEBRING, DEBORAH S. SNECKENBERGER, et al. "In Vivo Observation of Cavitation on Prosthetic Heart Valves." ASAIO JOURNAL 42, no. 5 (1996): M550–554. http://dx.doi.org/10.1097/00002480-199609000-00047.

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Lee, Hwansung, Tomonori Tsukiya, Akihiko Homma, et al. "Observation of cavitation bubbles in monoleaflet mechanical heart valves." Journal of Artificial Organs 7, no. 3 (2004): 121–27. http://dx.doi.org/10.1007/s10047-004-0258-8.

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Bordeasu, Ilare, Cornelia Laura Salcianu, Mircea Octavian Popoviciu, and Ion Mitelea. "Cavitation Erosion Resistance of Laser Beam Nitride Layers of X5CrNi18-10 Stainless Steel." Revista de Chimie 70, no. 2 (2019): 708–13. http://dx.doi.org/10.37358/rc.19.2.6990.

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The use of nitration in technical applications, as thermochemical treatment, regardless of the used method (ionic, gas or laser beam nitration) is realized to obtain a nitrogen rich layer, which increase the resistance to shock or abrasion, as a result of the high hardness obtained. All the previous cavitation researches showed that hardness is an important mechanical properties, for cavitation erosion resistance increase. The present paper show some results regarding the cavitation erosion behavior of laser beam nitrated layers. As basic material was used the austenitic stainless steel X5CrNi18-10. This material is frequently used for manufacturing details subjected to cavitation, such as valves, drawers of hydraulic distribution and regulation devices, or the retaining ring for butterfly valves. There were used three power regimes of the laser beams: 120 W, 180 W and 240 W. To obtain cavitation erosion was used the standard device with piezo-ceramic crystals of Timisoara Polytechnic University Cavitation Laboratory. The cavitation erosion comparisons, both with the basic material subjected only to the common thermochemical treatments and with the laboratory cavitation standard steel (OH12NDL), show that the nitrated surfaces presents increased cavitation erosion behavior, the principal factor being the important hardness increase of the nitrated layer. We mention also, that for higher laser beam powers the thickness of the nitrated layer increases. All the images obtained at the end of tests show that the cavitation exposure was stopped before overtaking the nitrated layer. So, all our results concern only the hardened layers.

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ANDRIOTIS, A., M. GAVAISES, and C. ARCOUMANIS. "Vortex flow and cavitation in diesel injector nozzles." Journal of Fluid Mechanics 610 (August 8, 2008): 195–215. http://dx.doi.org/10.1017/s0022112008002668.

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Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as ‘string-cavitation’. Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection events, implying significant hole-to-hole and cycle-to-cycle variations during the corresponding spray development.

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Yan, Jin, Yang Heng-hu, Yang Hong, et al. "Nondestructive Detection of Valves Using Acoustic Emission Technique." Advances in Materials Science and Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/749371.

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The applications of acoustic emission (AE) technique in detection of valves are presented in this review, and the theoretical models and experimental results of nondestructive detection of valves using AE are provided. The generation of AE signals and the basic composition of AE detection system are briefly explained. The applications of AE technique in valves are focused on condition monitoring, failure, cavitation detection, and the development of portable measuring devices. All results prove that the AE technique works well in the detection of valves.

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Micu, Lavinia Madalina, Iosif Lazar, Adrian Circiumaru, Ilare Bordeasu, Liviu Daniel Pirvulescu, and mihai Hluscu. "New Results Regarding Cavitation Behavior of Polymers Modified with Anorganic Substances Coated on Bronze Surfaces." Materiale Plastice 55, no. 3 (2018): 460–63. http://dx.doi.org/10.37358/mp.18.3.5051.

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Due to mechanical resistance characteristics, chemical corrosion and abrasive erosion resistance, the polymers are more widely used in equipments and installations that are exploited in different fluid hydrodynamic conditions. Among these applications there is the protection of surfaces of hydromechanic organs stressed by cavitation, like in hydraulic machines rotors and valves. Consequently, the research aimes the extension of using these and protection of other components surfacess hardly streesed by cavitation. The research in this paper points toward the behavior of modified polymer layer, coated on surfaces of bronze used in casting the propellers of maritim and river ships. The tests were performed in standard piezoceramic crystal vibrating equipment within Cavitation Laboratory of Politehnica University of Timisoara. The damaging intensity of equipment is much greater than any cavitational vortex, created by ship propeller, hydraulic turbine or centrifugal pump. The obtained results, compared to both recorded on uncovered surfaces with polymer layer and recorded on surfaces covered with HVOF composite materials layers, show an increased resistance that implies the increased exploiting duration of those surfaces.

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Lin, Hsin-Yi, Brian A. Bianccucci, Steven Deutsch, Arnold A. Fontaine, and J. M. Tarbell. "Observation and Quantification of Gas Bubble Formation on a Mechanical Heart Valve." Journal of Biomechanical Engineering 122, no. 4 (2000): 304–9. http://dx.doi.org/10.1115/1.1287171.

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Clinical studies using transcranial Doppler ultrasonography in patients with mechanical heart valves (MHV) have detected gaseous emboli. The relationship of gaseous emboli release and cavitation on MHV has been a subject of debate in the literature. To study the influence of cavitation and gas content on the formation and growth of stable gas bubbles, a mock circulatory loop, which employed a Medtronic-Hall pyrolytic carbon disk valve in the mitral position, was used. A high-speed video camera allowed observation of cavitation and gas bubble release on the inflow valve surfaces as a function of cavitation intensity and carbon dioxide CO2 concentration, while an ultrasonic monitoring system scanned the aortic outflow tract to quantify gas bubble production by calculating the gray scale levels of the images. In the absence of cavitation, no stable gas bubbles were formed. When gas bubbles were formed, they were first seen a few milliseconds after and in the vicinity of cavitation collapse. The volume of the gas bubbles detected in the aortic track increased with both increased CO2 and increased cavitation intensity. No correlation was observed between O2 concentration and bubble volume. We conclude that cavitation is an essential precursor to stable gas bubble formation, and CO2, the most soluble blood gas, is the major component of stable gas bubbles. [S0148-0731(00)00204-1]

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Yoon, Joon-yong, Seng-jun Lee, and Eun-suk Kim. "Numerical Analysis of Flows in Butterfly Valves to Prevent Cavitation." Journal of Fluid Machinery 7, no. 1 (2004): 9–16. http://dx.doi.org/10.5293/kfma.2004.7.1.009.

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OSHIMA, Ryoichiro. "A simple rule of cavitation inception in large butterfly-valves." Transactions of the Japan Society of Mechanical Engineers Series B 54, no. 504 (1988): 1885–90. http://dx.doi.org/10.1299/kikaib.54.1885.

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RAMMOHAN, Srambickal, Sivasankaran SASEENDRAN, and Sivasailam KUMARASWAMY. "Effect of Multi Jets on Cavitation Performance of Globe Valves." Journal of Fluid Science and Technology 4, no. 1 (2009): 128–37. http://dx.doi.org/10.1299/jfst.4.128.

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TAKIURA, Koki, Takahiro TOYAMA, Itsuro SAITO, Takashi ISOYAMA, Tsuneo CHINZEI, and Kou IMACHI. "Analysis of the Cavitation Phenomena on the Mechanical Heart Valves." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2002.14 (2002): 181–82. http://dx.doi.org/10.1299/jsmebio.2002.14.181.

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Gao, Zhi-xin, Yang Yue, Jia-yi Wu, Jun-ye Li, Hui Wu, and Zhi-jiang Jin. "The flow and cavitation characteristics of cage-type control valves." Engineering Applications of Computational Fluid Mechanics 15, no. 1 (2021): 951–63. http://dx.doi.org/10.1080/19942060.2021.1932604.

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Ahn, Y. J., B. J. Kim, and B. R. Shin. "Numerical Analysis on Flow Characteristics of High Pressure Drop Control Valves with Anti-Cavitation Trim." KSFM Journal of Fluid Machinery 10, no. 4 (2007): 61–70. http://dx.doi.org/10.5293/kfma.2007.10.4.061.

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Potoceanu, Nadia, Marian Dumitru Nedeloni, Daniel Chirus, and Danut Florea. "Cavitation Erosion Behavior of the Antifriction Alloy YSn83." Materials Science Forum 782 (April 2014): 257–62. http://dx.doi.org/10.4028/www.scientific.net/msf.782.257.

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This paper presents the cavitation erosion research of the antifriction alloy YSn83 regarding on its behavior in laboratory. The antifriction alloy YSn83 is not subject to cavitation erosion in its practical applications, as is happening in reality at the materials used in hydraulic turbines, valves, piping; but the experimental tests for this material, highlight the laboratory research on its behavior by means of images and graphs in this paper. The laboratory tests were performed in accordance with the standards G32-92 (Standard Method of Vibratory Cavitation Erosion Test) and G32-10 (Standard Test Method for Cavitation Erosion Using Vibratory Apparatus).

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Resch, M., and R. Scheidl. "A model for fluid stiction of quickly separating circular plates." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 9 (2013): 1540–56. http://dx.doi.org/10.1177/0954406213509613.

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Fluid stiction is a force which is created by the average pressure difference between a fluid-filled, narrow, quickly opening gap and the surrounding pressure. It plays a negative role in compressor valve technology and in fast switching valves, since it hinders an immediate response of the valves to a changing driving force situation. In this paper, the axisymmetric fluid stiction problem is studied by analytical mathematical models and experiments performed on a specific test rig. The study shows that the stiction force in narrow gaps is dominated by the viscous flow as described by the Reynolds equation for lubricating gaps and by cavitation which occurs in a centre region if the gap opening speed exceeds a critical value. The cavitation zone first extends and then shrinks and, finally, gives rise to complex oscillation phenomena due to the impact of the fluid when the cavitation zone collapses. It was found experimentally that fluids can create negative pressure for very short time. Measures to limit the stiction force are a large initial gap height or additional fluid supply channels from the surrounding to the gap.

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Sălcianu, Cornelia Laura, Ilare Bordeaşu, Nicușor Alin Sîrbu, et al. "Evaluation of the Cavitation Resistance of INCONEL 718, in Delivered and Respectively Heat Treated Condition." Advanced Materials Research 1157 (February 2020): 47–51. http://dx.doi.org/10.4028/www.scientific.net/amr.1157.47.

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Inconel 718 is a very difficult metal for machining because of its high plasticity. Lately, more and more researchers are interested in using it for cavitation parts, such as the plugs and drawers of the valves. For this purpose, thermal volumetric treatments have been initiated to facilitate mechanical machining, aiming simultaneously to obtain good compression and cavitation resistance results. Therefore, this paper presents the results of cavitation erosion behavior and cavitation resistance of ICONEL 718, subjected to two thermal treatment regimes, differentiated by the duration (temperature 800 °C and residence times 5 hours, and respectively 10 hours). The assessment of the cavitation resistance provided by each heat treatment regime is based on the average durability cavitation parameter, as defined by K. Steller. The research is achieved by using the standard vibrator device with piezo - ceramic crystals from the Cavitation Laboratory of the Politechnica University of Timisoara.

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