When using a steam turbine, where should the shaft be set in relation to the primary unit due to thermal growth?

When setting the shaft of a steam turbine in relation to the primary unit, it is crucial to account for thermal growth. Steam turbines operate under high temperatures, which can lead to expansion of the materials. If the shaft is set lower than the primary unit, it allows for the natural thermal expansion of the turbine to move upwards without causing misalignment or undue stress on the bearings and associated components.

This offset helps to maintain the proper alignment during operation at elevated temperatures, preventing issues such as increased wear or failure of the turbine. By positioning the shaft lower, you ensure that as temperatures rise and the shaft expands, it will still align properly with the rest of the system's components.

Other configurations, such as setting the shaft higher or even parallel, would not accommodate thermal expansion effectively and could lead to operational challenges. Dynamically parallel could imply a dynamic adjustment that is not typically feasible due to the fixed nature of many installations. Thus, setting the shaft lower is the most effective method to enhance performance and extend the lifespan of the turbine system.