# Cooling in Liquid Rocket:
The heat created during combustion in a rocket engine is contained within the exhaust gases. Most of this heat is expelled along with the gas that contains it; however, heat is transferred to the thrust chamber walls in quantities sufficient to require attention.
Regenerative cooling is the most widely used method of cooling a thrust chamber and is accomplished by flowing high-velocity coolant over the back side of the chamber hot gas wall to convectively cool the hot gas liner. The coolant with the heat input from cooling the liner is then discharged into the injector and utilized as a propellant.
Earlier thrust chamber designs, had low chamber pressure, low heat flux and low coolant pressure requirements, which could be satisfied by a simplified "double wall chamber" design with regenerative and film cooling.
For subsequent rocket engine applications, however, chamber pressures were increased and the cooling requirements became more difficult to satisfy. It became necessary to design new coolant configurations that were more efficient structurally and had improved heat transfer characteristics.
This led to the design of "tubular wall" thrust chambers, by far the most widely used design approach for the vast majority of large rocket engine applications. These chamber designs have been successfully used and several other Air Force and NASA rocket engine applications. The primary advantage of the design is its light weight and the large experience base that has accrued. But as chamber pressures and hot gas wall heat fluxes have continued to increase (>100 atm), still more effective methods have been needed.
One solution has been "channel wall" thrust chambers, so named because the hot gas wall cooling is accomplished by flowing coolant through rectangular channels, which are machined or formed into a hot gas liner fabricated from a high-conductivity material, such as copper or a copper alloy.. Heat transfer and structural characteristics are excellent.
Basically there are three domains in a regenerative cooled rocket engine.
Gas Domain (Combusted Gases) - Convection and Radiation heat transfer
Liquid Domain (Coolant) - Convection heat transfer
Solid Domain (Thrust chamber wall) - Conduction heat transfer
Heat transfer from the outer surface of thrust chamber to the environment can be neglected and the outer surface wall can be assumed as adiabatic.
In addition to the regenerative cooled designs mentioned above, other thrust chamber designs have been fabricated for rocket engines using dump cooling, film cooling, transpiration cooling, ablative liners and radiation cooling. Although regeneratively cooled combustion chambers have proven to be the best approach for cooling large liquid rocket engines, other methods of cooling have also been successfully used for cooling thrust chamber assemblies.
To get the updated and remaining notes of cooling in liquid rocket, please click the below link or visit our new website aerospacenotes.com...
https://aerospacenotes.com/propulsion-2/cooling-in-liquid-rocket/
https://aerospacenotes.com/propulsion-2/cooling-in-liquid-rocket/
Table of Contents:
- What Is Meant By Cooling In Liquid Rocket?
- Methods Of Cooling In Liquid Rocket
- Regenerative Cooling In Liquid Rocket
- Dump Cooling In Liquid Rocket
- Film Cooling In Liquid Rocket
- Transpiration Cooling In Liquid Rocket
- Ablative Cooling In Liquid Rocket
- Radiation Cooling In Liquid Rocket