Within the Expert experimental reentry vehicle programme , a control flap designed to withstand hypersonic thermal conditions during reentry was tested in the CIRA Scirocco plasma wind tunnel in Capua, near Naples, Italy.
The RUAG, ETHZ, CFSE, and SMR consortium was in charge of studying the heating of the flap with computer simulation, making use of computational fluid dynamics and computational heat transfer software. To this end, CFSE's NSMB fluid dynamics solver and SMR's B2000++ heat transfer solver were coupled with SMR's FScon/FSI coupling software.
The flap is equipped with a thermal camera looking at the back of the flap and measuring the temperature within a limited surface. The camera was equipped by ETHZ, which also made the measurements during the experimental campaign at CIRA.
The heat transfer FE model of the flap was coupled to the CFD flap and bottom plate for several CFD flow conditions. For each flow condition, a transient heat flow analysis was performed, taking into account the nonlinear behaviour of the flap material (Keraman) and the base plate material (Inconel) as well as radiation between the flap and the surrounding structure and radiation to infinity.
The video below displays the inner flap wall temperature [K] as a function of time. The angle of view is the same as the one of the camera measuring the temperature on the inner flap surface (see left figure). The structure is heated for 120 sec. Thereafter the heat flow is cut and the cooling process is observed during 80 sec.