Improvement of Characteristics of Gas Pressure Control System Using Porous Materials

Peng, Jiehong; Youn, Chongho; Takeuchi, Taku; Kagawa, Toshiharu

doi:10.4236/jfcmv.2015.34016

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…The working principle of an isothermal chamber is to fill a certain density of high thermal conductivity metal porous material inside the chamber to make the discharge process approximate to an isothermal process, thereby transforming a flow item that is difficult to accurately measure into a pressure item that is easy to measure. Therefore, isothermal chamber has a wide range of applications in the flow measurement of pneumatic field (Funaki et al, 2007;Kamali et al, 2016;Kato et al, 2009;Kawashima et al, 2003;Peng et al, 2015). However, in the actual application process, the air temperature inside the isothermal chamber is not strictly isothermal, and there is a certain amount of temperature change.…”

Section: Introductionmentioning

confidence: 99%

Modeling and simulation of the discharge process of isothermal chamber to determine the isothermal characteristic

Yang

Meng

2022

JTST

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Isothermal chamber is filled with a certain density of high thermal conductivity porous material, which has a wide range of applications in the flow measurement of pneumatic field, and its isothermal characteristic is critical to its application results. In this paper, in order to improve the numerical calculation accuracy of the isothermal characteristics during discharge process, a discharge model of isothermal chamber with fractal effective thermal conductivity (ETC) for determining the isothermal characteristic is reported. Firstly, the stuffer in isothermal chamber is considered as porous random fiber bundle, and an ETC prediction model of anisotropic porous random fiber bundle in both vertical and horizontal directions is established by fractal theory. This model with two directions is in good agreement with the experimental results, and the relative root mean square errors (RRMSE) are 3.94% and 9.85%, respectively. Secondly, the discharge model with fractal ETCs is built, and the isothermal characteristics of isothermal chambers with three different porosities are determined by numerical simulation. Finally, experiments to determine the isothermal characteristic are carried out. The numerical simulation results are in good agreement with the experimental results, and the relative errors are less than 3%. It could be concluded that accurately determining the ETC of the stuffer in isothermal chamber can improve the numerical calculation accuracy of the isothermal characteristic. Moreover, compared with the experimental method, numerical method is energy-saving and timesaving.

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Section: Introductionmentioning

confidence: 99%

Modeling and simulation of the discharge process of isothermal chamber to determine the isothermal characteristic

Yang

Meng

2022

JTST

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“…In our previous research study, 26 the dynamic characteristics of a pneumatic resistance-capacitance (RC) circuit with porous materials were investigated. In this study, a porous material is employed to stabilize the pilot valve system considering its linear flow resistance characteristics.…”

Section: Introductionmentioning

confidence: 99%

Stabilization of pilot valve system using linear flow resistance

Peng

Youn

Takeuchi

et al. 2017

Advances in Mechanical Engineering

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In a pilot valve system, the pressure in the control chamber of the main valve is straightforwardly affected by pressure oscillation in the downstream pipeline or the pilot tube. To solve this problem, an orifice is generally installed in the pilot tube to restrain the oscillation. However, the orifice is a nonlinear flow resistance; the amplitude of the oscillation alters the gain curve of the control pressure response. In this study, a linear flow resistance such as a porous material is employed to stabilize the pilot valve system. A test pilot valve was manufactured, and a pilot valve system was developed in the laboratory of the authors of this article. A mathematical model of the pilot valve system using linear and nonlinear flow resistances was simulated in MATLAB. The linearity of the P-Q characteristics of the linear flow resistance was confirmed, and a series of frequency response experiments were performed to examine the dynamic characteristics of the pilot valve system with various flow resistances. The experimental results were in accord with the simulation results. This implied that when porous materials were used in the pilot valve system, the gain of the pressure response did not vary regardless of the varying pressure vibration amplitude. Therefore, porous materials are suitable to be used in the pilot valve system instead of an orifice to enhance its stability.

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Variable viscous flow resistance based on rotational inertia

Shen

2023

Physics of Fluids

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Viscous flow resistance is dominated by viscous friction between fluid and wall. The flow resistance characteristic curve (i.e., the relationship curve between pressure drop and flow rates, represented as the Δp–Q curve) depends on some inherent characteristic variables, such as structural size, fluid viscosity, density, and temperature. Usually, to change the Δp–Q curve, these inherent characteristic variables must be changed. This paper proposes a new design of variable viscous flow resistance. The new design uses two disks to construct a slit flow channel, and rotate one of the disks to drive the fluid in the slit flow channel to form a rotational inertia effect. Therefore, by changing the rotating speed of the disk, the rotational inertia effect can be changed, thereby achieving the purpose of changing the Δp–Q curve. This paper derives a theoretical model for the pressure distribution of the rotating slit flow field and conducted experimental verification. It was found that the rotational inertia gradient and viscous gradient terms play major roles in governing the radial pressure gradient. The sum of the other two inertial gradient terms accounts for a maximum of about 1.58% of the total pressure gradient. There is a coupling relationship between circumferential velocity, radial velocity, and flow rates. An increase in Q can increase the rotational inertial gradient term by up to 24.9%. The rotating disk causes additional radial velocity and thus weakens the viscous gradient term by at least 16.41%.

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Improvement of Characteristics of Gas Pressure Control System Using Porous Materials

Cited by 3 publications

References 12 publications

Modeling and simulation of the discharge process of isothermal chamber to determine the isothermal characteristic

Modeling and simulation of the discharge process of isothermal chamber to determine the isothermal characteristic

Stabilization of pilot valve system using linear flow resistance

Variable viscous flow resistance based on rotational inertia

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