Marine diesel engine parts manufacturers analyze the thermal fatigue phenomenon of combustion chamber

The failure of combustion chamber components of Marine diesel engines under the action of alternating thermal stress is called thermal fatigue. The damage of thermal fatigue to the components of the combustion chamber starts from the crack, and gradually develops to make the components crack.

When the diesel engine is working, the thermal stress on the high temperature surface is compressive stress. If the plastic deformation is caused by the local creep of the combustor wall at high temperature, the residual tensile stress can not be restored due to the plastic deformation when the stop or the load is reduced and the wall temperature is reduced, and the compressive tensile stress is alternate. Since the change period of the alternating stress has nothing to do with the speed, but only depends on the start-run-stop or load change period, it is called low-frequency stress. Cracks, apparently caused by thermal fatigue, usually start from the high-temperature fire contact surface and gradually develop into fatigue damage.

High frequency stress: the stress change cycle is the same as the working cycle cycle of the diesel engine, and the frequency is higher. It has to do with rotational speed.

Low frequency stress: The stress change period is the same as the diesel engine start-run-stop or load change period, and the frequency is lower.