Turbojet engines are the first and simplest type of gas turbine engines. A basic of jet engines consist of air inlet, air compressor, combustion chamber, turbine, and exhaust nozzle.
The jet engines as part of an aviation engineering program which the objectives of this project were to (1) rebuild and repair for the jet engine demonstration laboratory; (2) to design the inlet attach to the SWIWIN SW60B turbojet engine; (3) to install new pressure sensor to measure the total pressure at the new inlet; (4) to measure actual thrust of engine and compare to the previous and calculation thrust; and (5) to measure, calibrate data from sensors by using LabVIEW program.
This experiment, the researchers decided to study on the effective of the inlet shape by create three design inlet consist of 95 millimeters diameter inlet, 100 millimeters diameter inlet, and 120 millimeter diameter inlet attach to the SWIWIN SW60B turbojet engine. From the previous senior project, the engine was installed seven sensors to measured air properties, thrust, and engine RPM. This project the new sensor to measure the pressure at the design inlet was installed and re-calibrate all the sensors. When experimenting, the measured data from sensors were sent to data acquisition system. After that the output data is sent to the personal computer with the LabVIEW program and showed on the ECU display. After the experiment finished, the data is recorded and then compared to the data of OEM inlet and plot the graphs, the different is shown the effectiveness of the air inlet shape.
The thrust produce from the jet engine depend on engine RPM and the inlet. It was found that in the range low RPM up to 30 percent throttle, 100 millimeter diameter inlet can produce the most measured thrust. For the higher RPM, 40-70 percent throttle is produce the most measured thrust with 95 millimeter diameter inlet and 80-100 percent throttle OEM inlet can produce the most measured thrust. The calculated thrust of inlet 100 millimeter diameter inlet is the best and also generate the least amount of additive drag. Even though no inlet has the highest value of thrust but it has no inlet, So the additive drag can not be calculated and mass flow rate is not reasonable.
This project provides to understanding about the fundamental knowledge, the method to increase the thrust of the jet engine by a focus on inlet shape and also opportunities to apply in an aircraft power plant.