F • CONVECTIVE HEAT TRANSFER IN GASES 



The above simple procedure using Eq. 7-lb, 7-2b, and 7-3b checks 

 shock tube experimental data of Rose and Riddell [72] very well for the 

 stagnation point of a sphere as seen in Fig. F,22h. A more elaborate theory 

 of Fay and Riddell [73], taking into account the effects of diffusion and 

 atomic recombination, also fits the data well, so that it would seem that 

 these latter effects do not significantly influence the heat transfer rate, 

 at least according to the above experiments. 



100 



E 



u 



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 <u 



(/) 



c 

 o 



o 



Q. 



c 

 _o 



o 

 c 

 en 

 o 



in 



12 16 20 24 



Flight velocity, (ft/sec) X IQ-^ 



Fig. F,22h. Comparison of theory and experiment on heat transfer 

 at the stagnation point of a sphere. 



While the above procedure produces good results for the calculation 

 of heat transfer from a dissociated gas, the actual over-all effect of disso- 

 ciation on the heat transfer rate for a perfect gas is shown in Fig. F,22i. 

 The calculation was made for a sphere at 100,000-feet altitude in the 

 ICAO (International Civil Aviation Organization) atmosphere, and the 

 wall temperature was assumed to be 2500°R. It is concluded that the 

 effect of dissociation (real gas) on heat transfer, compared to the perfect 

 gas solution, is not great. 



Turbulent flow. As with laminar flow, it can be shown that for turbu- 

 lent flow the effect of dissociation, compared to the perfect gas solution, 

 will also not be very great [74]. 



< 424 ) 



