| Description |
37 leaves : illustrations ; 29 cm |
| Summary |
"Transpiration cooling has long been known as an effective way of removing heat from porous materials. This thesis is a new approach to one of the problems of transpiration cooling in the steady state. The specific problem considered here is that of a uniform porous plate through which a liquid is forced. This liquid vaporizes at a short distance from the surface through which it is forced and leaves the porous plate at the other surface which is exposed to hot gases. It also protects the hot surface by forming an insulating layer between that surface and the hot gases. Pumping liquid rather than vapor is particularly efficient because of its absorption of heat in evaporation. It is assumed that there exists a finite temperature difference between the solid particles and the coolant in the adjacent pores. The solution of the problem is illustrated by an example employing high alumina refractory plate having a thickness slightly more than 0.1 ft. Cooling is provided by a uniform flow of water in a direction counter to the flow of heat, while one surface of the plate was heated by convection heat transfer by a hot gas. The temperature of the coolant leaving the plate is determined by the amount of heat flux, coolant mass rate of flow and the specific heat of the coolant. The temperature distribution in the coolant was calculated by solving the equations derived in this thesis on the Missouri School of Mines and Metallurgy LGP-30 Royal McBee Digital Computer. The result of this investigation proves that transpiration cooling is an effective way of cooling and that the temperature drop of the coolant near the hot face is larger than that near the other end allowing the use of relatively thin plates for transpiration cooling. It was also shown that values of film coefficient of 2 or greater than 2 give discontinuities in the temperature distribution curve of the coolant within the porous plate and that low thermal conductivities of the solid material give better effectiveness to this method of cooling"--Abstract, leaves 2-3. |
|
