Experiments on an Induction Type HighSpeed Wind Tunnel Driven by LowPressure Steam - Summary and Appendices

Sep 2, 2026

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Performance of an induction type high speed wind tunnel driven by low pressure steam (up to 1201b per sq in absolute) is investigated to about Mach 1.7. With suitable design, Mach number ranges are attainable across a wide span of supply pressures and steam quantities. Steam-driven results are comparable to earlier compressed-air experiments in required pressures and mass quantities. An approximate theoretical analysis is developed in the Appendix and practical adaptation of existing boiler plants is discussed.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages21

Reading Time53 min

AccessFree to download

2. Introduction

3. Apparatus

4. Preliminary Tests

5. Experimental Results

March,1949 Experiments on an Induction Type HighSpeed Wind Tunnel Driven by LowPressure Steam -by- G.M,Lilley,D.I.C.,M.Sc., of the Department of Aerodynamics and D.W.Holder,D.I.C.,A,C.G.I.,B.Sc.,of the Aerodynamics Division of theNational Physical Laboratory SUMMARY The performance of an induction type high speed wind tunnel drivenby low pressure steam(up to 1201b.per sq.in.absolute)has beeninvestigated up to a Mach number of about 1.7. It was found thatby suitable design a range of Mach numbers could be attained over awide range of supply pressures and steam quantities, Comparisonwith previous experiments in which compressed air was used to drivethe tunnel show that the required steam and air pressures and quantitiesare comparable. These results imply that in many cases existing boilerplants can readily be adapted to drive high speed tunnels of usefuldimensions. An approximate theoretical analysis of the performance of thistype of tunnel is developed in the Appendix. It is not anticipated that the method will have any large scaleapplications,but it is suggested that it may provide a simple andinexpensive method for installing small high speed tunnels inEngineering Colleges and similar establishments where a steam supplyis already available. This investigation was performed at the suggestion ofProfessor Cave-Browne-Cave of University College,Southampton inhis laboratories, GML/DMS —2— Symbols 1. velocity of sound(a²=YP/p) a A area of cross-section of mixing zone As area of the high pressure slot Aw area of the working section b and c constants in the Callendar equation ofstate for steam C a function of M5,the Mach number atthe end of thé mixing zone °p specific heat of dry air i total heat J mechanical equivalent of heat mass flow of dry air m1 mass flow of steam m2 M Mach number ratio of specific heats insupersaturated steam n p pressure Q mass flow of steam lb。per hourArea of working-section r Area of mi.xing zone R constant in equation of state T absolute temperature U velocity specific volume V ratio of specific heats in dry air Y ratio of specific heats in air-water-vapourmixture. Ym diffuser efficiency n mass flow of dry air μ mass flow of steam density P refers to conditions in compressedair receiver r refers to conditions in steam pressurechamber S refers to conditions of dry air atintake to tunnel Om refers to conditions of the air-water-vapour mixture downstream of themixing zone 1,2,3,5,6 refers to conditions at the respectivenumbered section on Fig.2. —4— # 2. Introduction Considerable experience has been obtained at theNational Physical Laboratory in the use of air injectiors todrive high speed wind tunnels,but the use of steam injectiorsfor this purpose appears to have received comparatively littleattention. The use of steam has been discussed by Poggi³andtunnels using steam at high pressures and superheat were builtin Germany between 1940 and 1945. More recently Professor Cave-Browne-Cave suggested that the method would have certain advantagesfor driving small high speed wind tunnels at Engineering Colleges,since if the boilers were available the remainder of the plant couldbe very simple and cheap. It was at his request that the presentexperiments were performed in his laboratories. The main experiments described below have been made onthe N.P.L。21/L,in.diameter tunnel using dry saturated and slightlysuperheated steam at pressures up to 1201b.per sq,in.absolute.Scme preliminary flow observations were however made with a 2 in.sq·glass-sided working section. # 3. Apparatus The flow of air through the working-section was inducedby a flow of low pressure steam(up to 1201b./sq.in.absolute)through an annular injector slot placed downstream of the working.section. The common flow was then discharged into a conicaldiffuser, The prs1iminary wor

FAQs

What range of Mach numbers does the steam-driven induction wind tunnel reach?

The experiments investigate tunnel performance up to a Mach number of about 1.7.

How does the study compare steam driving with earlier compressed-air driving?

The required steam and air pressures and quantities are found to be comparable to previous experiments using compressed air.

Why are boiler plants and engineering-college setups relevant to the proposed method?

Existing boiler plants can be adapted to drive high speed tunnels, offering a simple and inexpensive way to install small high speed tunnels where steam supply is available.

Sep 2, 2026

Uploaded by Paura