# Accession Number:

## AD0648254

# Title:

## TRANSPIRATION COOLING OF A CONSTRICTED ELECTRIC-ARC HEATER.

# Descriptive Note:

## Rept. for Jun 64-Dec 65,

# Corporate Author:

## MINNESOTA UNIV MINNEAPOLIS HEAT TRANSFER LAB

# Personal Author(s):

# Report Date:

## 1966-08-01

# Pagination or Media Count:

## 133.0

# Abstract:

A theoretical study has been made to estimate the potentialities of a constricted-arc gas heater in which the wall of the constrictor tube is transpiration cooled. By use of an integral form of the energy equation, it is found that the mass-average enthalpy reaches a maximum value in a distance, in tube diameters, of about half the ratio of the initial axial mass flux to the radial mass flux of the transpiring gas. When compressibility effects are small, the maximum is an asymptotic state. For this state the conservation equations are reduced to ordinary differential equations which are solved numerically for the case of hydrogen at atmospheric pressure. The graphical results show the relationship between blowing rate, power input, wall temperature, peak temperature, average enthalpy, electric field and current, and also distributions of various dependent variables. The range in which the solution is valid is determined from calculations of axial and radial pressure variations, Mach number, axial Reynolds number, and of the minimum blowing rate. From these considerations one can predict that a peak temperature of about 60,000K should be obtainable, but that the maximum mass-average enthalpy will be about the same as that obtainable from a water-cooled arc. Some results are presented to show the sensitivity of the solution to changes in the electrical conductivity, the radiated power and the radial velocity profile.

# Descriptors:

# Subject Categories:

- Air Conditioning, Heating, Lighting and Ventilating
- Plasma Physics and Magnetohydrodynamics