As part of building up its capabilities, the Indian Space Research Organisation (ISRO) is in the process of establishing a trisonic wind tunnel at the Vikram Sarabhai Space Centre (VSSC) here at Thumba.
Wind tunnels are large devices used to study the effects of air flows past solid objects; in this particular case, scale models of launch vehicles and spacecraft.
As the name suggests, the trisonic facility will enable the VSSC, which is the lead ISRO centre for launch vehicles, to carry out tests in three different speed regimes - subsonic, transonic, and supersonic.
The blow-down type wind tunnel under construction at the Thumba Equatorial Rocket Launching Station (TERLS) will have a simulation range of 0.2 Mach to Mach 4 speeds.
“We are planning to have the first blow-down in February 2022. It was planned for November this year, but the second wave of COVID-19 has caused some delay,” an ISRO official said.
So far, ISRO has been supported by the trisonic wind tunnel at the National Aerospace Laboratory (NAL), Bengaluru. But this facility is over 50 years old. Besides, the need for a trisonic wind tunnel of its own was deeply felt by ISRO given the heft of the space missions lined up for the immediate future such as the crewed Gaganyaan project.
Important parts of the wind tunnel include air storage vessels, a settling chamber where the air flow is ‘smoothened’, and nozzles through which the air is let into the test section.
The VSSC already has a hypersonic wind tunnel which is needed for testing parameters of re-entry missions. This facility, which can simulate flow speeds up to Mach 12, was commissioned in 2017.
The ISRO centre is in the process of piecing together the various components of the trisonic wind tunnel, a work which has been awarded to Tata Projects Ltd. A giant settling chamber for the wind tunnel which arrived at the Kollam port from Mumbai is currently on its way to Thumba by road on hydraulic-axle trailers.
