A Review on Flow Characteristics of the Straight and Coiled Capillary Tubes

Abstract

A detailed literature review on the flow characterization of the capillary tubes is presented in this paper. The flow behavior is reviewed for straight, helically, and spirally coiled capillary tubes at different operating and geometric conditions by considering various aspects in the tube. This paper summarizes experimental and numerical study on the adiabatic and nonadiabatic straight and coiled capillary tubes at different geometries conditions. The vital information of the range of the tube geometry and operating conditions are discussed, which can be utilized for further studies on the capillary tube. Various methodologies with generalized correlations are indicated. It has been observed that there are even more studies need to do with environmentally friendly refrigerants with various practical aspects in the capillary tube. It would be interesting to find the coiling effect on the design and simulation of the capillary tube. In addition to that more experimental and numerical studies need to explore the nonadiabatic coiled capillary tube. It would be fascinating to study the metastable condition in the capillary tube and set suitable relations to present its effect on the mass flow rate.