Experimental investigation of two phase flow instabilities in a horizontalin-tube boiling system

This research covers the experimental investigation of two phase flow insta bilities in a horizontal in-tube flow boiling system whose test tube is rel atively long. All experiments are conducted at constant heat input, system pressure and exit restriction. Steady state characteristics for five inlet temperatures are found and presented in pressure drop versus mass flow rate diagrams. Dynamic instabilities, such as pressure drop type, density wave type and thermal oscillations are found to occur for all the investigated t emperatures, and the boundaries for the appearance of these oscillations ar e found. As a result, the stability boundary moves to lower mass flow rates with decreasing inlet temperature, which means that the system is less sta ble for higher inlet temperatures. It is found that the periods and amplitu des of the pressure drop type and density wave type of oscillations decreas es with decreasing mass flow rate and increases with decreasing inlet tempe rature. In addition, it is found that the channel length has an important e ffect on the two phase flow dynamic instabilities. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.