TY - GEN
T1 - Two-Phase flow heat transfer under microgravity condition
AU - Parang, M.
AU - Tipton, J. B.
AU - Garth, J. D.
PY - 2003
Y1 - 2003
N2 - Two-phase flows under microgravity conditions appear in a large number of important applications in fluid handling and storage, and spacecraft thermal and power system (e.g., condensers, evaporators, piping system.) The physics of this ubiquitous flow is however very complex and not well understood. Through the NASA Reduced Gravity Student Flight Opportunity Program, a group of undergraduate students from the University of Tennessee had the privilege to investigate this issue in reduced gravity aboard the KC-135 "Weightless Wonder". The first objective of their experiment was to simulate two-phase flow using a mixture of liquid water and air. The second objective was to investigate the relationship between heat transfer and phase distribution in pipe flows. The experimental apparatus was designed, built and tested by the undergraduate students. It consisted of a closed water loop using clear 1" ID pipe and a centrifugal pump. Downstream of the pump, an aluminum manifold injected air circumferentially around the pipe wall to simulate twophase flow. The flow was then passed through a test section, which could be either a smooth pipe flow, or a flow through a pipe fitted with an augmentation device insert. After the inserts, a resistance heater supplied a constant heat flux to a six-inch section of pipe. Thermocouples before and after the heated section recorded the resulting change in flow temperature. The flow visualization indicates that in the smooth pipe flow a liquid water film remains attached to the pipe wall. The temperature measurements indicate a 15 to 20% reduction in heat transfer from the wall to the fluid for pipes with the insert. The heat transfer reduction is attributed to the removal and replacement of the liquid water film by the rapid mixing of the two phases caused by the flow through the pipe insert.
AB - Two-phase flows under microgravity conditions appear in a large number of important applications in fluid handling and storage, and spacecraft thermal and power system (e.g., condensers, evaporators, piping system.) The physics of this ubiquitous flow is however very complex and not well understood. Through the NASA Reduced Gravity Student Flight Opportunity Program, a group of undergraduate students from the University of Tennessee had the privilege to investigate this issue in reduced gravity aboard the KC-135 "Weightless Wonder". The first objective of their experiment was to simulate two-phase flow using a mixture of liquid water and air. The second objective was to investigate the relationship between heat transfer and phase distribution in pipe flows. The experimental apparatus was designed, built and tested by the undergraduate students. It consisted of a closed water loop using clear 1" ID pipe and a centrifugal pump. Downstream of the pump, an aluminum manifold injected air circumferentially around the pipe wall to simulate twophase flow. The flow was then passed through a test section, which could be either a smooth pipe flow, or a flow through a pipe fitted with an augmentation device insert. After the inserts, a resistance heater supplied a constant heat flux to a six-inch section of pipe. Thermocouples before and after the heated section recorded the resulting change in flow temperature. The flow visualization indicates that in the smooth pipe flow a liquid water film remains attached to the pipe wall. The temperature measurements indicate a 15 to 20% reduction in heat transfer from the wall to the fluid for pipes with the insert. The heat transfer reduction is attributed to the removal and replacement of the liquid water film by the rapid mixing of the two phases caused by the flow through the pipe insert.
UR - http://www.scopus.com/inward/record.url?scp=85087192240&partnerID=8YFLogxK
U2 - 10.2514/6.2003-1302
DO - 10.2514/6.2003-1302
M3 - Conference contribution
AN - SCOPUS:85087192240
SN - 9781624100994
T3 - 41st Aerospace Sciences Meeting and Exhibit
BT - 41st Aerospace Sciences Meeting and Exhibit
PB - American Institute of Aeronautics and Astronautics Inc.
T2 - 41st Aerospace Sciences Meeting and Exhibit 2003
Y2 - 6 January 2003 through 9 January 2003
ER -