Test bench with expansion and compatibility functions

The invention discloses a test bed with expansion and compatibility functions, and belongs to the field of gas turbine test beds. The invention relates to a large pull rod air pressure test device, which comprises an air main pipe, an exhaust main pipe, an air compressor, an electric heater, a test unit, an air branch pipe, an exhaust branch pipe and a large pull rod expansion joint, the air outlet of the air compressor is connected with the air inlet of the electric heater, and the air outlet of the electric heater is connected with the air main pipe through the large pull rod expansion joint; the other end of the test unit is communicated with the exhaust main pipe through an exhaust branch pipe, and a sliding support is arranged at an outlet of the electric heater. In order to solve the problems that in the prior art, test schemes are diverse, test beds matched with the test schemes are scarce, namely, one test bed can adapt to tests of different fuel combustion chamber characteristics and is low in manufa