ISRO conducts sea level test of cryogenic engine at 22 tonne thrust

• ISRO successfully conducted a sea level hot test of its cryogenic engine (CE20) at 22 tonne thrust using nozzle protection system and multi-element igniter.

• The test was conducted at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu, where the engine operated for 165 seconds.

• Earlier, the sea level tests utilising the nozzle protection system were being carried out at a 19-tonne thrust level.

• The CE20 cryogenic engine powers the upper cryogenic stage of the Launch Vehicle Mark-3 (LVM3).

• In order to enhance the payload capability, future missions of LVM3 are planned to be operated with an uprated C32 stage with 22 tonne thrust for the CE20 engine. 

• In view of this, the flight acceptance test of the CE20 engine also needs to be conducted at 22 tonne thrust level.

• Testing the CE20 engine at sea-level had considerable challenges primarily due to the high area ratio nozzle, which has an exit pressure of 50 mbar (millibar).

• A main concern during testing at sea-level include flow separation inside the nozzle, which leads to severe vibrations and thermal problems at the flow separation plane leading to possible mechanical damage of the nozzle. 

• To solve this problem, ISRO developed and used a nozzle protection system.

• The CE20 engine has now completed a record 20 successful hot tests. 

• The CE20 engine holds significance for India's upcoming Gaganyaan human spaceflight mission.

(The author is a trainer for Civil Services aspirants.)