A Sub Scale Investigation on Side Loads in Sea Level Rocket Nozzles

The challenge of designing first stage rocket engine nozzles is made more difficult by the unstable loads during the start-up and sea level rig testing. These side loads are a key issue for the nozzle designed. In order to understand this and to be able to optimise the future designs, Volvo is currently working with a broad program. With both tests and analysis. The program started within the GSTP framework in 1997 and is presently continuing as a National program closely co-ordinated with our European partners. Up to June 1999, not less than 7 test campaigns have been carried out, all at the facilities of FFA in Stockholm. The paper describes the objectives of these tests together with results and conclusions. In parallel work is ongoing to understand the side loads, their nature and the factors influencing their size. Analytical models have been developed and correlated to the test results. The future potential of the knowledge generated in this program is very high since the side load reduction design will be a powerful instrument in increasing the performance of the next generations sea level nozzles.