THE ANALYSES FOR THE CASING IMPROVEMENTS OF THE MPM-20 ENGINE

The operational issues of a small turbojet engine MPM 20 are discussed. The engine was created by modifying the Soviet turbostarter TS - 20B/21 designed for short-term operation. It is necessary to make structural modifications that allow for the long-term operational premise of the engine. For this purpose, several analyses were focused on the thermally stressed parts. The first, a material analysis carried out on the outer casing of the combustion chamber and on the combustor liner reveals information about the mechanical properties of these structural nodes. It was necessary since there is no documentation of the engine with this information. Another analysis of the infrared emission spectra is important for monitoring operational conditions, especially from the temperature point of view. Subsequent stress analysis of the casing is based on results from previous analyses. It was used to observe the behaviour of the casing as operational conditions changed. This revealed a dangerous increase of thermally induced stress levels as temperature increased up to 150 degrees C. Various structural modifications can be made in the future with these results, such as an application of a protective coating on the casing and combustor liner of the engine.(1)