Accession Number:

ADA220070

Title:

Water Heat Pipe Frozen Startup and Shutdown Transients with Internal Temperature, Pressure and Visual Observation

Descriptive Note:

Final rept. Sep 1984-May 1989

Corporate Author:

TEXAS A AND M UNIV COLLEGE STATION

Report Date:

1990-02-01

Pagination or Media Count:

337.0

Abstract:

Three sets of experiments were performed to analyze the transient nature of heat pipes and possible failures. The first set studied the entrainment phenomenon and suggests that entrainment starts in a form not readily observable by other than visual means. The second set used a specially designed heat pipe with a rectangular cross section, flat mesh-type wick, and a clear top through which internal mechanisms of heat pipe operation could be seen. These served as scoping experiments for the third set. The third set measured vapor space temperatures, wickliquid temperatures, and internal pressure. A normal start-up experiment, and experiment with step changes in input power levels, including previously unexpected pressure transients and two frozen start-ups, a step decrease in power input to the evaporator, and a steady-state run with decreasing secondary coolant temperature were performed. In addition to the experiments, a multinodal, implicit, finite difference model was developed to simulate heat pipe rapid transients. The mass, momentum, and energy conservation equations generate the velocity, pressure, and temperature profiles. The temperature profiles differed significantly from the experimental data, but the pressure and velocity profiles agree well with existing theory. Computer programs.

Subject Categories:

  • Air Conditioning, Heating, Lighting and Ventilating
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE