Experimental Study of the Model Compartment of the Low-Pressure Cylinder of K-320-240 Turbines of JSC "Turboatom"

Abstract

A reduction in the efficiency of the last stages of powerful steam turbines, as well as their reliability due to an increase in the disturbing forces acting on the blades, is an urgent study subject, which requires a comprehensive analysis of gas-dynamic processes in these parts of the turbines. To determine the integral and gas-dynamic characteristics of the last LP stages of K-320-240 turbines under variable operating conditions, and develop recommendations for their further improvement, experimental studies of the model flow path of the cylinder compartment were conducted using the gas-dynamic test stand 0102 of Turboatom JSC. As a result, it was established that closing the moisture removal slot increases the efficiency of the last LP stage by 2–7% in the range of volumetric steam flow rate changes from 900 to 2900 m3/s. With a nominal operating mode, the efficiency of the two penultimate LP stages is 0.786. With a significant change in the volumetric steam flow rate downstream of the last stage in the previously specified limits, the compartment efficiency changes by less than 0.9%. As a result of the experimental studies, there was determined the possibility of increasing the efficiency of the flow path of the K-320-23, 5-4 turbine LPC. The results of the above studies were used to modernize the K-320-240 turbines, which made it possible to increase the efficiency of the compartments of the last three LPC stages by 1.3%, of which 0.9% were due to the modernization of the third stage and 0.4%, due to the sealing of the fourth stage radial clearance, and use the results of the study to improve the LPC of the K-325-23.5 turbine.

Keywords

• volumetric steam flow rate
• low pressure cylinder
• steam turbine
• efficiency