Study on Flow and Transient Structural Response Characteristics of the Jacking Oil System in the Gas Turbines

The jacking oil system serves as a crucial safety barrier by injecting high-pressure oil into the bearings during the startup and shutdown of heavy-duty gas turbines. Taking the pipeline of the jacking oil system of the first domestically produced 300 MWF-class gas turbine as the research object, a coupled simulation method of computational fluid dynamics and transient structural dynamics was adopted. Focusing on the analysisof the water hammer effect caused by valve opening and the transient structural response of the pipeline, the significant influence of different valve opening times and characteristics on pressure wave propagation and pipeline vibration was revealed. Results show that both short valve opening time and rapid opening characteristics intensify fluid pressure oscillations and induce high-amplitude structural vibrations. Although an excessively long valve opening time can mitigate fluid impact, it also prolongs the reconstruction process of the flow field in the pipeline. To suppress the transient impact during valve operation, a valve opening strategy of "slow-rapid-slow" is proposed. The maximum equivalent stress (250.66 MPa) of the pipeline occurs at the intersection line of the tee, and the pipelinestrength meets the engineering requirements.