On the Flow in Steam-Generating Tubes of Once-Through Boilers : Part I. Fundamental Equations and their Solution

Abstract

The pressure drop in the once-through boiler tube is usually so large as to prohibit neglecting self-veaporation due to the change in the enthalpy of water and steam. Also, since the water enters the generating section at a temperature lower than the saturation point and leave the generating section in a state or dry saturated or superheatead steam, the change in the dryness through the tube is so large as to prohibit assuming uniform friction coefficient. Fundamental equations under the above-mentioned conditions are derived and solved in this paper. Also approximate solutions for the pressure distribution are derived by neglecting the self-evaporation and the change in the friction coefficient of two phase flow along the tube.