Measurement of Liquid Nitrogen Level using Thermoacoustic Spontaneous Gas Oscillation

A gas in a tube spontaneously oscillates when the temperature ratio between the tube ends exceeds a critical value. This spontaneous gas oscillation is applied to a liquid helium level finder. In the present study, to design a liquid nitrogen level finder using spontaneous gas oscillation, the critical value of the temperature ratio causing spontaneous gas oscillation for the case of nitrogen gas was numerically investigated. It was found that a tube in which an array of narrow circular tubes is located can work as a liquid nitrogen level finder. Hence, a tube with an array of narrow tubes was constructed and the liquid level of nitrogen put into a vessel was measured with the constructed tube. The measurements also demonstrated that the tube can work as a liquid nitrogen level finder.