Herman. Merte

Boiling Heat-Transfer Data for Liquid Nitrogen at Standard and Near-Zero Gravity

A program has been in progress at the University of Michigan for studying the role of force fields on heat-transfer processes, including boiling. Knowledge of the influence of the force field has become of recent importance for application to space technology. The gravity field on the. moon is 0. 17 that on earth, and force fields at or near zero and greatly in excess of atmospheric conditions may be present in orbiting satellites and space vehicles.

Pressurized discharge of liquid nitrogen from an uninsulated tank

Work on the discharge of liquid nitrogen from an uninsulated tank which is subjected to heating from the atmosphere has recently been completed. The objective of this investigation was to determine how various factors influence the mass of gas in the tank when the discharge process has been completed, and to determine how this amount of residual gas can be reduced to a minimum. This paper deals with two aspects of the investigation, namely, a study of temperature transients and boiloff rate without discharge, and secondly, the influence of the temperature of the pressurizing gas on the mass of gas in the tank when discharge is completed.

Boiling Heat Transfer to a Cryogenic Fluid in Both Low and High Gravity Fields

This chapter discusses results of experiments conducted to study boiling heat transfer to a cryogenic fluid in both low and high gravity fields. The chapter also outlines that with the short free-fall time available, a transient technique was adopted in which the time rate of change of enthalpy of a body would provide a measure of the heat transfer rate at its surface. The report also points out that data were taken by immersing the copper sphere, initially at room temperature, into the liquid nitrogen on the test package. Because of the large initial temperature difference, stable film boiling is first obtained. It is also observed in the results that nucleate boiling heat transfer data for liquid nitrogen was obtained in the range from standard to 20 times standard gravity. The results were shown to be extended and the bubble Froude number computed for several cryogenic liquids in pool boiling. The results also showed that non-boiling free convection is gravity sensitive as is the region of incipient boiling.