CHAPTER 6
PRACTICAL ROCKET ENGINE APPLICATION
For scaling purposes these experimental results for the copper foam and nickel
foam were used to determine what could possibly happen at rocket engine specifications.
The properties that were used to determine the heat transfer enhancement and pressure
drop are a combination of specifications known as well as some from page 333 of Rocket
Propulsion Elements [2]. The specifications used are as follows: wall thickness is 0.02
in, total flow area for the coolant is .566 in2, max heat flux is 60 Btu/in2s, and a max wall
temperature of 1400 R. Assumed properties were as follows: Reynolds number is
1,000,000, the pressure of the coolant is 1500 psi, and the temperature of the coolant at
the highest heat flux is 90 R. The coolant temperature provides us with a Prandtl number
of 1.22 and a conductivity of 0.0104 lb/s-R. Using the Nusselt number and the effective
conductivity correlations in chapter 4 the Nusselt number with foam is 2025.37 with a
porosity of 95%, and the effective conductivity is 0.024 lb/s-R with the foam
conductivity being .287 lb/s-R. By using these correlations an effective heat transfer
coefficient can be calculated, and is found to be 691.54 lb/ft-s-R. Using the Nusselt
correlation in chapter 4 for internal flow without foam the Nusselt number is 1570.91.
The heat transfer coefficient for the internal flow without foam is 228.99 lb/ft-s-R. We
also know that the heat flux is equal to the heat transfer coefficient multiplied by the
temperature difference between the wall and the coolant. Since the heat flux is going to
stay the same whether or not there is foam in the cooling channel we can then set the two