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Wu, P. K. S.

Publications and source records attributed to Wu, P. K. S..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Convective heat flux in a laser-heated thruster

An analysis is performed to estimate the convective heating to the wall in a laser-heated thruster on the basis of a solution of the laminar boundary-layer equations with variable transport properties. A local similiarity approximation is used, and it is assumed that the gas phase is in equilibrium. For the thruster described by Wu (1976), the temperature and pressure distributions along the nozzle are obtained from the core calculation. The similarity solutions and heat flux are obtained from the freestream conditions of the boundary layer, in order to determine if it is necessary to couple the boundary losses directly to the core calculation. In addition, the effects of mass injection on the convective heat transfer across the boundary layer with large density-viscosity product gradient are examined.

Wu, P. K. S.↗
NASA NTRS1976

Stability of laser heated flows

A local stability analysis is utilized to determine the stability of disturbances generated at each point along a nozzle of variable area ratio for a one-dimensional flow heated by laser radiation entering from the upstream direction. The governing equations for the quasi-one-dimensional flow without viscous dissipation, diffusion, and thermal conduction but including radiative heat transfer are given. The governing equations are combined to yield a relationship which governs the Mach number variation through the nozzle. The complete steady-state solution can be calculated from knowledge of the Mach number profile, the inlet conditions, and the laser power. The local stability analysis permits obtaining contour (or contours) of neutral stability. Solutions have been obtained for various nozzle configurations, but only one set of example calculations is presented. The results obtained indicate that the analysis serves as an important indicator as to where potential absorption wave phenomena may be initiated.

Wu, P. K. S.↗
NASA NTRS1975

Radiant energy absorption studies for laser propulsion

A study of the energy absorption mechanisms and fluid dynamic considerations for efficient conversion of high power laser radiation into a high velocity flow is presented. The objectives of the study are: (1) to determine the most effective absorption mechanisms for converting laser radiation into translational energy, and (2) to examine the requirements for transfer of the absorbed energy into a steady flow which is stable to disturbances in the absorption zone. A review of inverse Bremsstrahlung, molecular and particulate absorption mechanisms is considered and the steady flow and stability considerations for conversion of the laser power to a high velocity flow in a nozzle configuration is calculated. A quasi-one-dimensional flow through a nozzle was formulated under the assumptions of perfect gas.

Caledonia, G. E.↗