Designing and Optimizing Stirling Type Pulse Tube Cryocooler

Author Name : Adithyan A Kumar, Abhilash K, Ananya M, Aswin Suresh

DOI: https://doi.org/11.56025/IJARESM.2023.113231074

ABSTRACT

Pulse tube refrigerators are the latest technical instrument in the field of refrigeration engineering. So  they are preferred over other types of cryocoolers like Stirling and Gifford-McMahon coolers because of no moving parts in the cooler making the cooler widely useful for various purposes. Other ordinary refrigerators use a vapour compression cycle but the pulse tube utilizes oscillatory expansion and compression of gas present inside it. Pulse tube cryocooler has a long life compared to other refrigerators, high reliability and low vibration because of no solid piston moving. These coolers have vast applications like semiconductor manufacture and their endless use in the military for the cooling of infrared sensors. They are also used for the cooling of astronomical detectors. They are also used for pre-coolers of dilution refrigerators. They are used in space applications also.

In this work, the study of Stirling type IPT cryocooler is considered for CFD analysis using fluent present in ANSYS22 workbench. 2D axis-symmetric geometry is created and used for CFD analysis. The simulations represent a fully-coupled system operating in steady periodic mode, with a trapezoidal pressure profile. Nothing is assumed rather than ideal gas and no gravity effect. The boundary conditions applied to this model are an oscillating pressure of the trapezoid profile created using a user-defined function (UDF), thermal boundary conditions like adiabatic and known heat flux at the cold end heat exchanger. The purpose is to study the Inertance Pulse tube cryocooler (IPTR) using CFD fluent analysis Where dimensions of components of IPTR are taken from Cha Jeesung's thesis [1] for values of an optimum result. To observe refrigeration pressure waves of the same specification like frequency and amplitude are applied for both cases as described. For each condition, two separate analyses are done. We assume the known condition of the cold-end heat exchanger (CHX); the other assumes isothermal or known cooling heat load. Each analysis was started with initial conditions and carried on until steady periodic conditions are attained. The unsteady CFD model successfully predicts IPTR performance by solving an ideal gas equation and heat transfer. The result is discussed in the Result and Discussion section.