F 22 • DISSOCIATION EFFECTS 



cooling was attempted. The following empirical formula fitted fairly well 

 the data from the five nozzle- wall segments: 



h = 0.029 





CpM 



(21-1) 



where h is the heat transfer coefficient in BTU/ft^ hr (°F) and is equal to 

 the product StCp^peiie- Also in Eq. 21-1, G is the mass velocity (at mid- 

 point of a segment) in lb mass/ft^ hr, D the inside nozzle diameter at a 

 segment midpoint in feet, Cp the specific heat of the gas at the insulated- 

 wall temperature in BTU/lb mass F, n the viscosity of the gas at the 

 insulated-wall temperature in lb mass/ft hr. It is interesting to note that 

 in spite of the rapid changes in the flow properties throughout the rocket 

 nozzle, Eq. 21-1 has the same form as empirical laws for turbulent flow 

 in straight pipes [59]. 



F,22. Dissociation EflFects. When the speed of an aircraft becomes 

 so great that the temperature of the surrounding air (owing to com- 



0.40 



O 0.35 



X 



u 



o 

 u 



o 



o 

 u 



CO 



*> 



<D 



-t— 



o 



< 



0.30 



0.25 



0.20 



0.15 



0.10 



0.05 







14 



2 4 6 8 10 12 



Temperature, °R X lO'^ 



Fig. F,22b. Absolute viscosity of air as a function of temperature and pressure.]^ 



(419 > 



