Analysis of Thermodynamic Effects on Cavitation Instabilities

2007 ◽  
Vol 129 (9) ◽  
pp. 1123-1130 ◽  
Author(s):  
Satoshi Watanabe ◽  
Tatsuya Hidaka ◽  
Hironori Horiguchi ◽  
Akinori Furukawa ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Heat Exchange ◽  
Cold Water ◽  
Research Needs ◽  
Cryogenic Fluids ◽  
Singularity Method ◽  
Thermodynamic Effect ◽  
Thermodynamic Effects ◽  
Suction Performance ◽  
Surrounding Liquid ◽  
Better Than

The suction performance of turbopumps in cryogenic fluids is basically much better than that in cold water because of the thermodynamic effect of cavitation. However, it is not still clear how the thermodynamic effect works on cavitation instabilities, such as rotating cavitation and cavitation surge. In the present study, the unsteady heat exchange between the cavity and the surrounding liquid is taken into account in a stability analysis using a singularity method. The results are qualitatively compared to existing experiments to clarify the research needs for deeper understanding.

Analysis of Thermodynamic Effects on Cavitation Instabilities

2006 ◽  
Author(s):  
Satoshi Watanabe ◽  
Tatsuya Hidaka ◽  
Hironori Horiguchi ◽  
Akinori Furukawa ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Heat Exchange ◽  
Cold Water ◽  
Research Needs ◽  
Cryogenic Fluids ◽  
Singularity Method ◽  
Thermodynamic Effect ◽  
Thermodynamic Effects ◽  
Suction Performance ◽  
Surrounding Liquid ◽  
Better Than

The suction performance of turbopumps in cryogenic fluids is basically much better than that in cold water because of thermodynamic effect of cavitation. However, it is not still clear how the thermodynamic effect works on cavitation instabilities such as rotating cavitation and cavitation surge. In the present study, the unsteady heat exchange between cavity and surrounding liquid is taken into account in a stability analysis using a singularity method. The results are qualitatively compared with existing experiments to clarify the research needs for deeper understanding.

Steady Analysis of the Thermodynamic Effect of Partial Cavitation Using the Singularity Method

2006 ◽  
Vol 129 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Satoshi Watanabe ◽  
Tatsuya Hidaka ◽  
Hironori Horiguchi ◽  
Akinori Furukawa ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Cold Water ◽  
Flow Analysis ◽  
Conduction Model ◽  
Cryogenic Fluids ◽  
Singularity Method ◽  
Partial Cavitation ◽  
Thermodynamic Effect ◽  
Unsteady Heat Conduction ◽  
Suction Performance ◽  
Better Than

It is well known that the suction performance of turbopumps in cryogenic fluids is much better than that in cold water because of the thermodynamic effect of cavitation. In the present study, an analytical method to simulate partially cavitating flow with the thermodynamic effect in a cascade is proposed; heat transfer between the cavity and the ambient fluid is modeled by a one-dimensional unsteady heat conduction model under the slender body approximation and is coupled with a flow analysis using singularity methods. In this report, the steady analysis is performed and the results are compared with those of experiments to validate the model of the present analysis. This analysis can be easily extended into unsteady stability analysis for cavitation instabilities such as rotating cavitation and cavitation surge.

Steady Analysis of Thermodynamic Effect of Partial Cavitation Using Singularity Method

2005 ◽  
Author(s):  
Satoshi Watanabe ◽  
Tatsuya Hidaka ◽  
Hironori Horiguchi ◽  
Akinori Furukawa ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Cold Water ◽  
Flow Analysis ◽  
Conduction Model ◽  
Cryogenic Fluids ◽  
Singularity Method ◽  
Partial Cavitation ◽  
Thermodynamic Effect ◽  
Unsteady Heat Conduction ◽  
Suction Performance ◽  
Better Than

It is well known that the suction performance of turbopumps in cryogenic fluids is much better than that in cold water because of thermodynamic effect of cavitation. In the present study, an analytical method to simulate partially cavitating flow with the thermodynamic effect in a cascade is proposed; heat transfer between the cavity and the ambient fluid is modeled by one-dimensional unsteady heat conduction model under the slender body approximation and is coupled with a flow analysis using singularity methods. In this report, the steady analysis is performed and the results are compared with those of experiments to validate the model of the present analysis. This analysis can be easily extended into unsteady stability analysis for cavitation instabilities such as rotating cavitation and cavitation surge.

Numerical Analysis of Airfoil NACA0015 and Centrifugal Pump’s Cavitation Characteristic Based on the Thermodynamic Effects

2009 ◽  
Author(s):  
Demin Liu ◽  
Shuhong Liu ◽  
Yulin Wu ◽  
Hongyuan Xu
Keyword(s):  
High Temperature ◽  
Pressure Coefficient ◽  
Cavitation Model ◽  
Cryogenic Fluids ◽  
Cavitation Characteristic ◽  
Thermodynamic Effects ◽  
C 50 ◽  
Suction Performance ◽  
Temperature Water ◽  
Better Than

Cavitation is not only driven by the pressure difference, but also affected by the temperature difference. In high temperature water or cryogenic fluids, temperature decline of liquids is caused by latent heat of vaporization. The cavitation characteristics in this conditions are different from that of room temperature. The thermodynamic effects of cavitation have very important application in the fluid machine, so high temperature and low temperature cavitation are comprehensively applied at the astronautics. The presented paper researched thermodynamics cavitation based on the Rayleigh-Plesset equation and deduced a new thermodynamics cavitation model with fully considering thermodynamic effects on the basic transport equation. The airfoil NACA0015 was calculated by the new model and the thermal cavitation characteristic was calculated at different temperature, that is, 25°C, 50°C and 100°C. Besides, the pressure coefficient was contrasted with experiment data at different temperature. The centrifugal pump’s suction performance curve was calculated at 25°C and 100°C respectively, and the main conclusion is that the suction performance of the pump at the high temperature is better than that at the normal temperature. The thermodynamic effects of cavitation model are more accurate at predicated centrifugal pump’s suction performance, which can provide beneficial referenced indicator for energy conservation.

scholarly journals Theoretical Analysis of Thermodynamic Effect of Cavitation in Cryogenic Inducer Using Singularity Method

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
S. Watanabe ◽  
A. Furukawa ◽  
Y. Yoshida
Keyword(s):  
Latent Heat ◽  
Heat Extraction ◽  
Singularity Method ◽  
Real Fluid ◽  
Thermodynamic Effect ◽  
Fluid Properties ◽  
Heat Of Evaporation ◽  
Suction Performance ◽  
R 114 ◽  
Surrounding Liquid

Vapor production in cavitation extracts the latent heat of evaporation from the surrounding liquid, which decreases the local temperature, and hence the local vapor pressure in the vicinity of cavity. This is called thermodynamic/thermal effect of cavitation and leads to the good suction performance of cryogenic turbopumps. We have already established the simple analysis of partially cavitating flow with the thermodynamic effect, where the latent heat extraction and the heat transfer between the cavity and the ambient fluid are taken into account. In the present study, we carry out the analysis for cavitating inducer and compare it with the experimental data available from literatures using Freon R-114 and liquid nitrogen. It is found that the present analysis can simulate fairly well the thermodynamic effect of cavitation and some modification of the analysis considering the real fluid properties, that is, saturation characteristic, is favorable for more qualitative agreement.

Thermodynamic Effect on Sub-Synchronous Rotating Cavitation and Surge Mode Oscillation in a Space Inducer

2009 ◽  
Author(s):  
Yoshiki Yoshida ◽  
Hideaki Nanri ◽  
Kengo Kikuta ◽  
Yusuke Kazami ◽  
Yuka Iga ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Cold Water ◽  
Acoustic Resonance ◽  
Pipe System ◽  
Thermodynamic Effect ◽  
Mode Oscillation ◽  
Cavitation Instability ◽  
Different Temperatures ◽  
Thermodynamic Effects ◽  
The Relationship

The relationship between the thermodynamic effect and sub-synchronous rotating cavitation was investigated with a focus on cavity fluctuations. Experiments on a three-bladed inducer were conducted with liquid nitrogen at different temperatures (74 K, 78K and 83 K) to confirm the dependence of the thermodynamic effects. Sub-synchronous rotating cavitation appeared at lower cavitation numbers in liquid nitrogen at 74 K, the same as in cold water. In contrast, in liquid nitrogen at 83 K, the occurrence of sub-synchronous rotating cavitation was suppressed because of the increase of the thermodynamic effect due to the rising temperature. Furthermore, unevenness of cavity length under synchronous rotating cavitation at 83 K was also decreased by the thermodynamic effect. However, surge mode oscillation occurred simultaneously under this weakened synchronous rotating cavitation. Cavity lengths on the blades oscillated with the same phase and maintained the uneven cavity pattern. It was inferred that the thermodynamic effect weakened the peripheral cavitation instability, i.e., synchronous rotating cavitation, and thus axial cavitation instability, i.e., surge mode oscillation, was easily induced due to the synchronization of the cavity fluctuation with an acoustic resonance in the present experimental inlet-pipe system.

Thermodynamic Effect on Subsynchronous Rotating Cavitation and Surge Mode Oscillation in a Space Inducer

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Yoshiki Yoshida ◽  
Hideaki Nanri ◽  
Kengo Kikuta ◽  
Yusuke Kazami ◽  
Yuka Iga ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Cold Water ◽  
Acoustic Resonance ◽  
Pipe System ◽  
Thermodynamic Effect ◽  
Mode Oscillation ◽  
Cavitation Instability ◽  
Different Temperatures ◽  
Thermodynamic Effects ◽  
The Relationship

The relationship between the thermodynamic effect and subsynchronous rotating cavitation was investigated with a focus on cavity fluctuations. Experiments on a three-bladed inducer were conducted with liquid nitrogen at different temperatures (74, 78, and 83 K) to confirm the dependence of the thermodynamic effects. Subsynchronous rotating cavitation appeared at lower cavitation numbers in liquid nitrogen at 74 K, the same as in cold water. In contrast, in liquid nitrogen at 83 K the occurrence of subsynchronous rotating cavitation was suppressed because of the increase of the thermodynamic effect due to the rising temperature. Furthermore, unevenness of cavity length under synchronous rotating cavitation at 83 K was also decreased by the thermodynamic effect. However, surge mode oscillation occurred simultaneously under this weakened synchronous rotating cavitation. Cavity lengths on the blades oscillated with the same phase and maintained the uneven cavity pattern. It was inferred that the thermodynamic effect weakened peripheral cavitation instability, i.e., synchronous rotating cavitation, and thus axial cavitation instability, i.e., surge mode oscillation, was easily induced due to the synchronization of the cavity fluctuation with an acoustic resonance in the present experimental inlet-pipe system.

Influence of Rotational Speed on Thermodynamic Effect in a Cavitating Inducer

2009 ◽  
Author(s):  
Kengo Kikuta ◽  
Yoshiki Yoshida ◽  
Tomoyuki Hashimoto ◽  
Hideaki Nanri ◽  
Tsutomu Mizuno ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Rotational Speed ◽  
Cavity Length ◽  
Cold Water ◽  
Thermodynamic Effect ◽  
Suction Performance ◽  
Temperature Depression

To estimate the influence of velocity on the thermodynamic effect, we conducted experiments in which the inducer rotational speed was changed in liquid nitrogen. The experiments in liquid nitrogen and in cold water allowed us to estimate the amplitude of the thermodynamic effect. In the experiment with lower rotational speed, suction performance was improved. The cavity length at lower rotational speed was shorter than that at higher speed. Thus, we confirmed that the degree of the thermodynamic effect depends on the rotational speed as lower rotational speed suppresses cavity length. Temperature depression was estimated based on a comparison of cavity length in liquid nitrogen and that in water. We found that the degree of temperature depression became smaller when the rotational speed was lower.

Development and Validation of a Reduced Critical Radius Model for Cryogenic Cavitation

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Shin-ichi Tsuda ◽  
Naoki Tani ◽  
Nobuhiro Yamanishi
Keyword(s):  
Heat Transfer ◽  
Temperature Change ◽  
Latent Heat ◽  
Energy Equation ◽  
Critical Radius ◽  
Liquid Oxygen ◽  
Design Phase ◽  
Cryogenic Fluids ◽  
Thermodynamic Effect ◽  
Suction Performance

Cryogenic fluids such as liquid hydrogen, liquid oxygen, and liquid methane have often been used as liquid rocket propellants, and it is well known that the suction performance of turbopump inducers is better in cryogenic fluids than it is in cold water due to the so-called “thermodynamic effect.” The origin of the thermodynamic effect is the temperature change inside a cavity region that arises from the latent heat transfer across the interface of a cavity. To better understand the suction performance of cavitating cryogenic inducers, we must take into account the temperature changes that take place due to the thermodynamic effect; computational fluid dynamics (CFD) analysis coupled with an energy equation is one of the most powerful tools for this purpose. The computational cost, however, becomes an obstacle for its application to the design phase, so a reduction in the number of governing equations is often preferable. In the present study, a cryogenic cavitation model that does not need to solve an energy equation is proposed as a reduced model; the model is named the “reduced critical radius model.” This model assumes that the temperature change due to the latent heat transfer can be analytically well estimated on the basis of an approximation of the local equilibrium when the pressure inside a cavity is always kept at a saturation vapor pressure at every temperature (at least on the time scale of the flow field). The proposed method was validated carefully for a variety of objects: blunt headforms, hydrofoils, a two-dimensional blunt wing, and Laval nozzles. The results obtained during the validation were in good agreement with the experimental results, except in the case of strong unsteady cavitation. This indicates that the present method, which does not involve solving an energy equation, offers good potential for application to the design phase of cryogenic cavitating inducers.

scholarly journals Influence of Thermodynamic Effect on Blade Load in a Cavitating Inducer

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Kengo Kikuta ◽  
Noriyuki Shimiya ◽  
Tomoyuki Hashimoto ◽  
Mitsuru Shimagaki ◽  
Hideaki Nanri ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Liquid Nitrogen ◽  
Cavity Length ◽  
Cold Water ◽  
Pressure Rise ◽  
Cavitation Number ◽  
Design Parameters ◽  
Trailing Edge ◽  
Thermodynamic Effect ◽  
Blade Tip

Distribution of the blade load is one of the design parameters for a cavitating inducer. For experimental investigation of the thermodynamic effect on the blade load, we conducted experiments in both cold water and liquid nitrogen. The thermodynamic effect on cavitation notably appears in this cryogenic fluid although it can be disregarded in cold water. In these experiments, the pressure rise along the blade tip was measured. In water, the pressure increased almost linearly from the leading edge to the trailing edge at higher cavitation number. After that, with a decrease of cavitation number, pressure rise occurred only near the trailing edge. On the other hand, in liquid nitrogen, the pressure distribution was similar to that in water at a higher cavitation number, even if the cavitation number as a cavitation parameter decreased. Because the cavitation growth is suppressed by the thermodynamic effect, the distribution of the blade load does not change even at lower cavitation number. By contrast, the pressure distribution in liquid nitrogen has the same tendency as that in water if the cavity length at the blade tip is taken as a cavitation indication. From these results, it was found that the shift of the blade load to the trailing edge depended on the increase of cavity length, and that the distribution of blade load was indicated only by the cavity length independent of the thermodynamic effect.

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