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A Study on the Effects of Temperature in Air Leak Detection

Author: MaLin
Tutor: DuJingMin；LiJinYun
School: Huazhong University of Science and Technology
Course: Mechanical and Electronic Engineering
Keywords: Airtight detection Pressure Temperature Leak rate Heat transfer coefficient
CLC: TH89
Type: Master's thesis
Year: 2011
Downloads: 18
Quote: 0
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Abstract

In modern industrial production and daily life, airtight detection technology has become a guarantee of product quality, energy conservation, and protection of the environment an integral part, due to the special nature of the gas, making a great influence on the temperature of the test results. The gas direct pressure and differential pressure detection system mathematical model to address the problem, and the ambient temperature on the test results of the system through simulation and experimental analysis. First of all, according to the gas dynamics and thermodynamics theory to establish a mathematical model of the process of cavity leakage. Gas direct pressure detection and differential detection process, the influence of the ambient temperature on the the accommodating cavity gas pressure, temperature, and the containing chamber leak rate through numerical simulation analysis results showed that: a detection method using direct pressure barotropic detection process, the temperature was raised when the cavity leakage rate slows down, the the drop the Wen Shirong chamber leakage rate of decline faster. The case of micro-leakage, Yung cavity gas temperature to return to ambient temperature before the actual leak rate of the differential pressure detection method of detecting leakage rate hematocrit chamber; gas temperature to return to ambient temperature, smaller leak rate detected by the differential pressure detection method in the cavity of the actual leak rate. The volume of the cavity, the leak detection greater the pressure, the greater the differential pressure detection method of calculating leakage rate measured cavity leakage rate deviation. Secondly, the design and establishment of a direct pressure detection system test bed, the preparation of a system based on LabVIEW software platform control software, at room temperature, the ambient temperature in the heating and cooling process of direct pressure test results experimental study results show that: in the micro- The leakage process gas leakage Yung cavity temperature less affected. Positive pressure testing process, the leakage rate of the cavity with the capacity decreased and the temperature rise of the cavity of the gas pressure decreases; negative pressure detection process, the leak rate of the cavity with the accommodating cavity gas pressure and temperature rise in less small. In the cavity and smaller temperature changes, the equivalent heat transfer coefficient of the cavity is decreased, with the accommodating cavity gas temperature rise with the accommodating cavity gas temperature drop increases. Finally, the proposed method based on detection of pressure and cavity leakage rate of the heat transfer coefficient, contrast detection method detects leakage rate generally direct pressure analyzed based on the detection effect of cavity leakage rate detection method detects pressure and heat transfer coefficient. The test results show that: in the case of smaller heat transfer coefficient of the cavity, the leak rate detection method based on the detected pressure and the volume chambers of the heat transfer coefficient of the influence of the environmental temperature on the detection result can be significantly reduced. The subject laid the theoretical and experimental foundation for further study of the influence of temperature airtight detection system.

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