Study for coating effect of various materials in pulse tube of pulse tube refrigerator

Shuttle heat transfer loss is one of the losses generated in a pulse tube and considerably influences the performance of a pulse tube refrigerator. If the inner wall of a pulse tube is perfectly maintained at adiabatic condition, the shuttle heat transfer loss can be eliminated. Near adiabatic condition may be achieved in the inner wall of a pulse tube if it is coated by poor thermal conductor like teflon. This paper focuses on the analysis and the experimental study for the effect of coating in a pulse tube of a pulse tube refrigerator. First, the effect of coating is analyzed from the 2D numerical simulation. In this process, various artificial materials are selected as the whole component of the wall of a pulse tube and the effect of material is examined by calculating the net enthalpy flow at the cold side of the pulse tube. When the wall consists of teflon, the quantity of the net enthalpy flow is maximized among the comparison cases. Second, a pulse tube refrigerator is fabricated to confirm the actual effect of coating in the pulse tube. The inner wall of the pulse tube is coated with various materials in consideration of heat penetration depth. The cooling capacities of a pulse tube refrigerator are carefully measured and compared to examine the effect of coating. The result of this paper can be used as the practical method that improves the performance of a pulse tube refrigerator. (c) 2012 Elsevier Ltd. All rights reserved.