Engineering topics
Publications and source records attributed to Powell, W. B..
A thermocouple assembly which includes a plug having a pair of small diameter holes near one end thereof which are spaced a small distance apart to leave a thin quantity of plug material between the holes is presented. There are a pair of thermocouple wires extending through the different holes and with the outer ends of the wires joined to the thin quantity of plug material which lies between the holes to form a thermocouple junction.
Passages of injector have been modified to eliminate backsplashing. All fluid is expelled in downstream spray fan. Result is that face of injector is completely free of liquid obstructions.
A methodology is described for the analysis of a transient temperature measurement made in a flat or curved plate subjected to convective heat transfer, such that the surface heat flux, the hot-gas temperture, and the gas heat transfer coefficient can be determined. It is shown that if the transient temperature measurement is made at a particular point located nearly midway in the thickness of the plate there is an important simplification in the data analysis process, in that the factor relating the surface heat flux to the measured rate of rise of temperature becomes invariant for a Fourier Number above 0.60 and for all values of the Biot Number. Parameters are derived, tabulated, and plotted which enable straightforward determination of the surface heat flux, the hot-gas temperature, of the plate, the rate of rise of temperature, the plate thickness and curvature, and the mean thermal properties of the plate material at the test temperature.
Thrust chamber performance is evaluated in terms of an analytical model incorporating all the loss processes that occur in a real rocket motor. The important loss processes in the real thrust chamber were identified, and a methodology and recommended procedure for predicting real thrust chamber vacuum specific impulse were developed. Simplified equations for the calculation of vacuum specific impulse are developed to relate the delivered performance (both vacuum specific impulse and characteristic velocity) to the ideal performance as degraded by the losses corresponding to a specified list of loss processes. These simplified equations enable the various performance loss components, and the corresponding efficiencies, to be quantified separately (except that interaction effects are arbitrarily assigned in the process). The loss and efficiency expressions presented can be used to evaluate experimentally measured thrust chamber performance, to direct development effort into the areas most likely to yield improvements in performance, and as a basis to predict performance of related thrust chamber configurations.
Oxygen difluoride/diborane propellant thrust chamber and injector technology, discussing engine duty cycles and performance
Hydraulic characteristics of micro-orifices arrayed in close proximity across the face of a liquid fuel injector are studied. Effects of geometry and flow variables on discharge coefficients and flow regimes are determined, as well as visible characteristics of the emerging liquid streams.
Oxygen difluoride/diborane propellant thrust chamber and injector technology, discussing engine duty cycles and performance
Hydraulic characteristics of flow through miniature slot orifices for rocket engine injectors, observing stability of effluent liquid streams
ICRPG liquid propellant thrust chamber performance evaluation methodology, reviewing imperfections and limitations
Hydraulic characteristics of flow through miniature slot orifices for rocket engine injectors
ICRPG liquid propellant thrust chamber performance evaluation methodology, reviewing imperfections and limitations
Local heat flux to isotropic plane or cylinder calculated from transient temperature measurements with application to rocket motor testing
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