Overview of Dynamic Sealing Systems for a LOX-Kerosene Turbopump in Liquid Rocket Engines

Liquid rocket engines are among the most complex machines ever created. High energy propellants are pumped by using high speed turbopumps and combusted to generate the required thrust for a launch vehicle. When the propellants used are cryogenically cooled, they pose concern due to the difficulty in handling the extreme thermal conditions. The mixing of the incompatible fluids could cause catastrophic failures to the launch vehicle. Hence, sealing systems are employed to prevent or minimize the interaction between such fluids. ISRO is presently in the process of developing a pump-fed liquid rocket engine employing liquid oxygen (LOX) and kerosene as propellants. The presence of large thermal gradients in the turbopump makes the sealing system quite complex and challenging, especially while designing with reuse capability. The present paper discusses the various dynamic seals that are employed in the turbopump.