Experimental test apparatus for heat transfer and fluid flow studies in multi-phase flow systems

Abstract

The present work deals with a conceptual design of a new experimental test rig, both for heat transfer and uid ow studies in a near wall region as well as for ow interaction and pressure drop studies in multi-phase ow systems. The test facility, which is going to be built at Reactor Engineering Division of Jo zef Stefan Institute in Ljubljana (Slovenia) was designed to perform experiments over wide range of test conditions, i.e., mass uxes ranging from 50 to 1700 kgm-2s-1, use of low and high pressure uids, while allowing a wide range of saturation temperatures. Several design issues have been dealt with in this work. The refrigerant R134a was chosen as the reference uid for the calculation purposes. Thermo physical and transport properties were interpolated from the NIST (National Institute of Standards and Technology) data tables over a wide range of test conditions. We focused on primary loop's components in general, while preheater was studied in detail. In order to calculate the exact length of this tube-in-tube counter-current heat exchanger, a numerical calculation procedure was developed in MATLAB code. To satisfy all the boundary conditions the code adopted an iterative approach at multiple levels. Once the heat exchanger's nominal length was calculated, a set of test conditions was systematically varied so as to estimate the e ect of each individual parameter on calculated length. Other components such as Coriolis-e ect mass ow meters, pumps and piping were also studied herein to provide guidelines for their nal acquisition. Indeed, the overall calculated pressure drop within the loop had to be coped with the available head of the selected pump while proposing a design without cavitation issues. Calculation of the secondary loops was not a subject of the present work.