Where is the highest gas pressure found in a turbojet engine?

The highest gas pressure in a turbojet engine is found at the entrance of the burner section. This is because, during the operation of the engine, air enters through the compressor where it is compressed, significantly raising its pressure before it moves into the burner section. Once the compressed air reaches the burner, fuel is injected, and combustion occurs, further increasing the pressure due to the rapid expansion of the hot gases produced from burning the fuel. As a result, the gases at this stage of the process are under high pressure, which is essential for efficient engine operation and maximizing thrust.

In contrast, other locations in the engine experience lower pressures due to various processes. For example, the exhaust duct primarily handles the high-speed exhaust gases exiting the turbine, which have often expanded and cooled, resulting in lower pressure. At the entrance of the compressor, air is still being drawn in and compressed, but it hasn't reached the peak pressure that occurs at the burner entrance. Similarly, at the turbine exit, the gases have expanded significantly to do work on the turbine blades, which leads to a drop in pressure as the energy is extracted from the gas flow.