F • CONVECTIVE HEAT TRANSFER IN GASES 



The enthalpy-temperature data for air as an ideal gas (see Fig. F,5b), 

 necessary for the calculation of density and viscosity in the solution of 

 the momentum equation (Eq. 3-8), were obtained from NBS-NACA 

 Table 2.10 which provides data up to 5400°R. The data were extrapolated 

 to higher temperatures. Since the specific heat is appreciably constant 

 up to about 1000°R, the greatest effect of specific heat variation is in the 

 free flight condition where the temperatures are greatest. 



0.86 



0.85 



0.84 



'■'r> 

 Q. 



0.83 



0.82 



0.68 



0.70 



0.72 



0.74 



Pr 



Fig. F,5d. Recovery factor for constant Prandtl 

 number and Blasius shear distribution. 



Fig. F,5c shows the viscosity variation as a function of temperature. 

 Except for the Hirschfelder portion below 216°R, the Sutherland law of 

 NBS-NACA Table 2.39 was used. 



Eq. 3-8 and 3-9 were solved numerically by hand using the trapezoidal 

 rule, the interval Aw^ being taken extremely small over the outer half 

 of the boundary layer. Consequently, the calculations were accurate to 

 approximately one part in ten thousand. The accuracy is indicated in 

 Fig. F,5d and F,5e where some recovery and Reynolds analogy factors 



( 352 > 



