NASA-TR-R-171-1967 The correlation of oblique shock parameters for ratios of specific heats from 1 to 5 3 with application to real gas flows《从1至5 3比热斜震参数与真实气流应用的联系》.pdf
《NASA-TR-R-171-1967 The correlation of oblique shock parameters for ratios of specific heats from 1 to 5 3 with application to real gas flows《从1至5 3比热斜震参数与真实气流应用的联系》.pdf》由会员分享,可在线阅读,更多相关《NASA-TR-R-171-1967 The correlation of oblique shock parameters for ratios of specific heats from 1 to 5 3 with application to real gas flows《从1至5 3比热斜震参数与真实气流应用的联系》.pdf(73页珍藏版)》请在麦多课文档分享上搜索。
1、m NASA NASA TR R-171 - “- e, f L z THE CORRELATION OF OBLIQUE SHOCK PARAMETERS FOR RATIOS OF SPECIFIC HEATS FROM 1 ,TO 5 /3 WITH . APPLICATION TO REAL GAS ,FLOWS NATIONAL AERONAUTICS AND SPACE ADMINtSTRATION WASHINGTON, D. C. DECEMBER 1963 Provided by IHSNot for ResaleNo reproduction or networking p
2、ermitted without license from IHS-,-,-TECH LIBRARY KAFB, NM 0067958 THE CORRELATION OF OBLIQUE SHOCK PARAMETERS FOR MTIOS OF SPECIFIC HEATS FROM 1 TO 5/3 WITH APPLICATION TO REAL GAS FLOWS By Mitchel H. Bertram and Barbara S. Cook Langley Research Center Langley Station, Hampton, Va. NATIONAL AERONA
3、UTICS AND SPACE ADMINISTRATION For sale by the Office of Technical Services, Department of Commerce, Washington, D.C. 20230 - Price $1.75 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-THE CORRELATION OF OBLIQUE SHOCK PARAMETERS FOR RATIOS OF SPECIF
4、IC HEATS FROM 1 TO 5/3 WITH AFPLICATION TO REAL GAS FLOWS By Mitchel H. Bertram and Barbara S. Cook An analytic investigation was made to show the extent of correlation of the exact oblique shock parameters that may be accomplished by means of similarity parameters suggested by approximate theory. T
5、he exact theory for the inviscid flow of a perfect gas was calculated for Mach numbers of 1.1 to 40, ratios of specific heats from 1 to 5/3, and angles of attack from 0 to shock detachment. From consideration of the approximate theory and the concept of effective ratio of specific heats, the oblique
6、 shock correlations were found to be useful for the rapid calculation of many flow parameters for an equilibrium real gas. Some use- ful correlations are also given for the case of isentropic expansion around a sharp corner. INTRODUCTION Two-dimensional oblique shock theory is one of the basic tools
7、 in aerodynamic work. Tables and charts are now available for results from two-dimensional oblique shock theory for the two gases most widely used in wind-tunnel work, air and helium, over extensive ranges of Mach number. (See refs. 1 to 8, for example.) In reference 9, the desire for air-helium tra
8、nsformations prompted an examination of the oblique shock similarity laws. This examination was for the first-order case with Mach number approaching infinity and some higher order approximations with the air-helium comparison paramount. There are cases where oblique shock parameters are desired for
9、 gases other than air or helium or where existing tables for a gas are inadequate. In these cases, the possibility of using existing tables or charts for gases other than the one of interest to obtain the desired information is suggested by similarity considerations. This analytic investigation was
10、undertaken to determine the correlating powers of certain similarity parameters suggested by approximate theory. Some comparisons with approximate theories were also made. In order to have as wide a comparison as possible, Mach numbers from the low supersonic to the hypersonic range have been includ
11、ed, deflection angles from 0 to shock detachment, and ratios of specific heats from unity to 5/3 in inviscid flow. From consideration of the approximate theory and the effective ratio of specific heats concept, the oblique shock correlations were found useful for the rapid calculation of many flow p
12、arameters for an equilibrium real gas. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SYMBOLS CP pressure coefficient h static enthalpy K flow deflectton similarity parameter (see eq. (5) Kp (7 + 1) ( 1 -2) Kpu 2 (7 + 1) (l - -) PmUm p22 M Mach numb
13、er P pressure T temperature U velocity 7 isentropic exponent ; equal to ratio of specific heats for a perfect gas 7e 6 * flow deflection angle effective value of 7 for flow across shock waves (eq. (16) e angle between free-stt-eam flow direction and shock wave ,P ,. density Subscripts : 2 condition
14、behind shock wake co free-stream conditions N normal to shock wave S at constant entropy 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t total pressure Superscripts in parentheses refer to series. PRESENTATION the order of an equation developed i
15、n OF THEORY 8, First let us examine some sample results from exact two-dimensional oblique shock theory for a perfect gas with a constant value for the ratio of specific heats. (See ref. 2, for example. ) Two Mach numbers have been chosen; one is (KPY %) much better than given by the uncorrelated fo
16、rm examples in figures 1(a) 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-one can readily note that at a given Mach number the first set of computations to deviate from correlation is that for 7 = 5/3, the next, the 7 = 1.4 results, and so on. On
17、e finds by comparing the results between the various parts of figure 2 that for therefore, the total-pressure ratio which is plotted in figure 11 does not contain the values for 7 = 1. This ratio is plotted in figure 11 as a function of the wedge deflection correlation param- eter. Mach numbers from
18、 1.1 to 40 are shown for a constant value of 7. One finds that for values of the deflection parameter below roughly 2, the ratio of total pressures is virtually independent of the value of 7 assumed. However, for values of the deflection parameter greater than about 2, the total-pressure ratio becom
19、es a strong function of the value of 7 assumed. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-APPLICATION TO A REAL GAS In a relatively simple manner, a method can be derived which allows the preceding correlations to be used for evaluation of ma
20、ny of the oblique shock parameters in a real gas. From mass flow and geometrical considerations uN 2 tan 0 ” uN,2 p, - (15) As given by Trimpi and Jones (ref. 8), an effective value of the isentropic exponent ye is used to describe the density change across the oblique shock applied to a real gas in
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