• Energy Research

This paper presents research related to the tubular combustion chamber of an expendable turbojet. Although annular combustors are dominant at present, tubular combustors are still attractive because they are simpler to produce and require lower amounts of air flow for testing. The objective of this research was to assess the combustor’s primary zone configuration, and four configurations were tested to obtain experimental answers for use in future work. The configuration of the combustion chamber is a simple and classic design in line with its expendable purpose. The test methodology was to perform initial testing of the primary and secondary zones under atmospheric conditions using the four configurations, and then to subsequently complete the combustor using the best configuration. The complete combustor was then tested under both atmospheric conditions and working conditions. The results showed that the stability margin was wide enough to cover the combustor’s entire working area. The measured efficiency and pressure drop were in very good agreement with the corresponding designed values. The design and testing methodology proposed here could be used for similar scientific and engineering research applications.

The operation of gas generators brings relatively high thermo-mechanical loads on the gas generator structure. The objective of this article is to determine the operating conditions, in terms of mechanical loads at extremely high temperatures in very limited and narrow space, of a multifunctional bulkhead for application on specific kinds of gas generators with back-to-back rotor concept. The paper contains numerical analysis and experimental investigation for determining the loads and behavior of the structure. Numerical analysis indicates that there is significant influence of the Tesla turbine effect on flow parameters. Also, uneven pressure distribution and significant thermal loads are identified. With experimental investigation and subsequent exploitation tests, it was concluded that the presented methodology identifies the operating conditions, truthfully simulates the bulkhead stress state and deformations and that the presented design solution satisfied all demands. Regarding results obtained by these numerical simulations, the innovative design solution for the multifunctional bulkhead was proposed.