Bengaluru, March 12 ISRO announced on Thursday that it had successfully conducted a sea-level hot test of its cryogenic engine (CE20) at 22 tonne thrust using a nozzle protection system and a multi-element igniter at its Propulsion Complex in Mahendragiri, Tamil Nadu.
Previously, sea-level tests using the nozzle protection system had been conducted at a 19-tonne thrust level.
The CE20 cryogenic engine powers the upper cryogenic stage of the Launch Vehicle Mark-3 (LVM3).
"To enhance the payload capability of the LVM3 vehicle, future missions of LVM3 are planned to be operated with an upgraded C32 stage with 22-tonne thrust for the CE20 engine. In this regard, the flight acceptance test of the CE20 engine also needs to be conducted at 22-tonne thrust level," ISRO said in a post on its website.
"Therefore, the current test (on March 10) successfully qualified the engine for sea-level testing, with a test duration of 165 seconds at 22-tonne thrust level, using the Nozzle Protection System (NPS). The performance of the engine, as well as the test facility, was as expected throughout the test duration," it said.
Noting that testing the CE20 engine at sea level presents significant challenges, primarily due to the high area ratio nozzle, which has an exit pressure of ~50 mbar (millibar), the space agency said, "A major concern during sea-level testing is flow separation inside the nozzle, which leads to severe vibrations and thermal problems at the flow separation plane, potentially causing damage to the nozzle."
"The cryogenic engine used for this test has undergone a record maximum number of hot tests (20 Nos), which has enabled the demonstration of several key technologies using a single engine, such as engine ignition using a multi-element igniter, ignition margin demonstration for Gaganyaan over a wide range of propellant tank pressures, and pre-ignition chamber pressure qualification for Gaganyaan at 20-tonne thrust level," it added.