Abstract
This paper presents the first study on how the unbalance of temperature recovery after air charged has a significant effect on the accuracy and repeatability of air leak detection. From this viewpoint, temperature recovery time is derived and affecting parameters are investigated. In a leak detection based on differential pressure measurement, the leak is detected by measuring pressure difference between a reference component, which is leak tight, and a tested component using a differential pressure sensor. When the tested component is leaking, the pressure inside it decreases and the pressure difference with the reference is measured. However, when the required temperature recovery time is not satisfied, unbalance of temperature recovery due to a possibly small difference of heat transfer coefficient between the reference and tested component can produce pressure difference that is similar in size as a real leak and larger uncertainty. This phenomenon is described theoretically and the experimental data are in satisfactory agreement with the calculated results.
