Experimental and numerical investigation on the flow of mixed refrigerants through capillary tubes at cryogenic temperatures. (5th July 2020)

• Record Type: Journal Article
• Authors: Parmar, Darshit; Atrey, M.D.
• Is Part Of: Applied thermal engineering. Volume 175(2020)
• Publication Date: 2020-07-05
• Subjects: Mixed refrigerant Joule-Thompson cryocooler -- Capillary tubes -- Pressure drop; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2020.115339
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Pressure drop through capillary for cryogenic refrigerant mixtures is studied. Two phase viscosity correlations are studied at cryogenic temperatures. Experiments have been carried out for cryogenic refrigerant mixtures. Abstract: Capillary tubes are the simplest form of expansion devices used in J-T refrigerators. Numerous researchers have worked on the flow of refrigerant through capillary tubes; however, only a few researchers have reported on flow through capillary tubes at cryogenic temperatures. This study focusses on the flow of refrigerant mixtures at cryogenic temperature through the capillary tube of a Mixed Refrigerant Joule-Thompson (MRJT) cryocooler. In order to design a capillary tube for such mixtures, a numerical model, which predicts pressure drop across the capillary tube, is developed in the present work. As the flow through the capillary is in two-phase region, the homogeneous flow model is employed in this analysis and various two-phase viscosity models are investigated. An algorithm to predict the design length of the capillary tube using the homogeneous flow model is developed. Experimentation is carried out to compare the same with the theoretical predictions. The model predicts capillary tube length with an accuracy of 20%.