Investigation of aerodynamic and energy characteristics of L.P.C. compartment of stages with inlet pipe and leak system for powerful steam turbine unit

Abstract

The results of computational and engineering developments and numerical studies of the inlet pipe compartment with the first three stages are represented, taking into account the steam extraction, leak ages under the diaphragms, shroud seals and discharge openings in the disks of low pressure cylinder of the turbine K-1250-6,9/25. All the computations were based on the model of one speed wet steam flow without droplets and supercooling was not taken into account. The sectorial approach was applied to description of the interaction of the inlet pipe and the group stages. The stages were considered in steady state formulation. The initial data and boundary conditions were taken basing on thermal design of ²TURBOATOM². Some methodological aspects and the results of improving of studied facilities by numerical experiment by MTFS® code are discussed. It is shown that the main total pressure loss in inlet pipe arises in collector and in place of its connection with tube. The improvement of inlet pipe annular collector due to the profiled sheets and input tube knee reduces the internal loss coefficient in 2 times. The axial length of the radial-axial outlet channel increase and the height of the splitter reduction almost no effect on the internal losses, but significantly (by 45%) reduce the coefficient of circumferential non-uniformity of static pressure at the stage inlet. Based on the item-evaluation of the effectiveness the final version of the inlet (M7) is developed. It is revealed that the inlet flow angles on the nozzle edges in the left and right sides of the inlet pipe are substantially symmetrical, i.e. the back effect of stages on the inlet pipe is small. The KE loss on the nozzles of 1st stage in the different sectors is different; on sectors of 1st blade row the loss and load are uniform. This effect persists for the next stages. Studies of the first three stages of the compartment based on leaks through the seal and discharge openings, sucking and suction, steam extraction showed that the root suctions behind the nozzles comply with the recommendations of MEI. Design of new seal for blade rows of 1st and 2nd stages in real boundary conditions showed a relatively high efficiency and the weak dependence on flow rate for axial position of the rotor relatively to the stator. // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o