2D22 Experimental investigation of effective bulk modulus of oil with entrained air bubbles(The 12th International Conference on Motion and Vibration Control)

2014 ◽  
Vol 2014.12 (0) ◽  
pp. _2D22-1_-_2D22-8_
Author(s):  
Yutaka TANAKA ◽  
Sayako SAKAMA ◽  
Hiroyuki GOTO
Keyword(s):  
Experimental Investigation ◽  
Bulk Modulus ◽  
Vibration Control ◽  
Air Bubbles ◽  
International Conference ◽  
Effective Bulk Modulus ◽  
Entrained Air

Modeling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hossein Gholizadeh ◽  
Doug Bitner ◽  
Richard Burton ◽  
Greg Schoenau
Keyword(s):  
Experimental Data ◽  
Bulk Modulus ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Air Bubbles ◽  
Pressure Sensitivity ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Experimental Apparatus ◽  
Major Factors

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air are not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution, and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models, and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.

The Variation of Oil Effective Bulk Modulus With Pressure in Hydraulic Systems

1994 ◽  
Vol 116 (1) ◽  
pp. 146-150 ◽  
Author(s):  
Yu Jinghong ◽  
Chen Zhaoneng ◽  
Lu Yuanzhang
Keyword(s):  
Experimental Investigation ◽  
Parameter Identification ◽  
Bulk Modulus ◽  
Hydraulic System ◽  
Theoretical Modeling ◽  
Model Parameters ◽  
Hydraulic Systems ◽  
Pressure Sensitive ◽  
Effective Bulk Modulus

The paper presents theoretical modeling and an experimental investigation of the variation of oil effective bulk modulus (βe) with pressure in hydraulic systems. A pressure sensitive model of βe and its several simplified forms have been derived. In addition, a method for parameter identification has been formulated. In an actual hydraulic system, values for βe at different load pressures were obtained, model parameters identified and modelling errors evaluated.

Modelling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air

2013 ◽  
Author(s):  
Hossein Gholizadeh ◽  
Doug Bitner ◽  
Richard Burton ◽  
Greg Schoenau
Keyword(s):  
Experimental Data ◽  
Bulk Modulus ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Air Bubbles ◽  
Pressure Sensitivity ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Experimental Apparatus ◽  
Major Factors

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air is not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.

Measurement of Effective Bulk Modulus for Hydraulic Oil at Low Pressure

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Sunghun Kim ◽  
Hubertus Murrenhoff
Keyword(s):  
Bulk Modulus ◽  
Volume Change ◽  
Suction Side ◽  
Pressure Change ◽  
Low Pressure ◽  
Simulation Accuracy ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Entrained Air ◽  
Low Pressures

Oil properties are very important input parameters for the simulation of hydraulic components. Precise values of effective bulk modulus at low pressures are especially required to improve the simulation accuracy of the pumps suction side or of cavitation in pumps or valves. So far, theoretical equations to compute the effective bulk modulus of hydraulic oil have not been experimentally verified, and only poor measured data are available to calculate the effective bulk modulus at low pressure. Therefore in this paper, the theoretical equation was verified for effective bulk moduli based on measurements of pressure change as a function of volume change at low pressures, varying temperature, entrained air content, and type of state change. Furthermore, the comparison of effective bulk moduli calculated with three different methods (mass-change, volume-change, and sound-speed method) shows that the effective bulk modulus can be calculated well from the measurement results of all three methods. The calculated effective bulk moduli values show little variation among the methods. Additionally, the release pressure of dissolved air in oil and the change of the polytropic gas constant depending on the speed of volume change rate were identified in this study.

Optimal Bounds on the Effective Bulk Modulus of Polycrystals

1989 ◽  
Vol 49 (3) ◽  
pp. 824-837 ◽  
Author(s):  
Marco Avellaneda ◽  
Graeme W. Milton
Keyword(s):  
Bulk Modulus ◽  
Effective Bulk Modulus ◽  
Optimal Bounds
Sign in / Sign up

Export Citation Format

Share Document