Forced-injection quenching of a hot-tube under microgravity
Abstract
The two-phase flow and boiling heat transfer characteristics have been investigated for quenching of a hot tube under microgravity. A 14 mm I.D., 1.2 m long quartz tube was initially heated to 300-400 C and then injected with liquid freon (R-113). The two-phase flow patterns were photographed and the temperature responses of the tube wall at various axial locations recorded on board NASA's KC-135 airplane. Long, continuous filaments of liquid and large droplets were seen to flow mostly in the middle of the tube, being unable to rewet the tube wall because of the thick vapor film existing between the liquid and the hot wall. Heat transfer was in either film boiling or forced convection to vapor, and the heat transfer rates were seen to be much lower than those in 1-g under the similar operating conditions. The results indicate that quenching may be significantly delayed under microgravity due to the inefficient precursory cooling prior to quench.
- Publication:
-
Forum on Microgravity Flows - 1991
- Pub Date:
- 1991
- Bibcode:
- 1991fmgf.conf....1K
- Keywords:
-
- Heat Transfer;
- Liquid Injection;
- Pipes (Tubes);
- Quenching (Cooling);
- Reduced Gravity;
- Wall Temperature;
- C-135 Aircraft;
- Film Boiling;
- Liquid-Vapor Interfaces;
- Loss Of Coolant;
- Two Phase Flow;
- Fluid Mechanics and Heat Transfer