tailieunhanh - THE DEVELOPMENT AND UTILIZATION OF SOME EQUIPMENT FOR LOW REYNOLDS NUMBER SUPERSONIC FLOW RESEARCH

In considering the overall workstation design, we must start with an analysis of the tasks which need to be performed there. No amount of ergonomic furniture can solve a situation where there is simply insufficient space. For example, as computer technology has been introduced into some offices, the computers or their terminals often have simply been placed onto existing desks, thus using up a large proportion of the space which is still needed for clerical tasks. The "paperless" office is still a long way from being achieved, so it is usually necessary to design for both keyboard. | THE DEVELOPMENT AND UTILIZATION OF SOME EQUIPMENT FOR LOW REYNOLDS NUMBER SUPERSONIC FLOW RESEARCH Thesis by Raymond L. Chuan In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy California Institute of Technology Pasadena California 1953 -i- ACKNOWLEDGMENTS The writer wishes to thank his adviser Professor H. w. Liepmann for initiating the research program which led eventually to the present work and for his continued interest helpful advice and enlightening criticism in the course of the execution of the investigation. The construction and successful operation of the equipment could not have been possible without the assistance of Mr. R. J. Magnus who designed and built many of the components of the tunnel and associated instruments. The friendly and patient assistance of other members of the GALCIT staff and particularly of Mrs. E. Fox Mrs. B. Cottingham and Mrs. B. Wood in the preparation of the thesis is gratefully acknowledged. ii AB STR ACT A low Reynolds number supersonic wind tunnel is a useful tool for the investigation of viscous effects in a high-speed flow. In order to avoid some of the difficulties inherent in a conventional wind tunnel system when operating at low Reynolds numbers a two-phase cycle is proposed. By examining the thermodynamics of the wind tunnel the relative merits of two methods of operation -- the one-phase cycle and the two-phase cycle -- are compared indicating certain advantages the two-phase cycle possesses over the conventional one-phase cycle when the tunnel is operated at high-speed and low Reynolds number. The design construction and operation of a small about 5 cm. test section area supersonic M-2 wind tunnel using a two-phase cycle with water in liquid and vapor phases as the working medium are described. Difficulties in pressure measurement and flow visualization due to the nature of the working medium and the low density of the flow are encountered. Means of meeting these difficulties are .