A Novel Dehumidification Strategy to Reduce Liquid Fraction and Condensation Loss in Steam Turbines

Abstract

Massive droplets can be generated to form two-phase flow in steam turbines, leading to erosion issues to the blades and reduces the reliability of the components. A condensing two-phase flow model was developed to assess the flow structure and loss considering the nonequilibrium condensation phenomenon due to the high expansion behaviour in the transonic flow in linear blade cascades. A novel dehumidification strategy was proposed by introducing turbulent disturbances on the suction side. The results show that the Wilson point of the nonequilibrium condensation process was delayed by increasing the inlet superheated level at the entrance of the blade cascade. With an increase in the inlet superheated level of 25 K, the liquid fraction and condensation loss significantly reduced by 79% and 73%, respectively. The newly designed turbine blades not only remarkably kept the liquid phase region away from the blade walls but also significantly reduced 28.1% averaged liquid fraction and 47.5% condensation loss compared to the original geometry. The results provide an insight to understand the formation and evaporation of the condensed droplets inside steam turbines.

Thermal Power Plant with 1 GW Capacity for Meeting Future National Electric Demands

“…The turbine shaft is coupled with the shaft of an electric generator, which is responsible of converting this mechanical power (shaft rotation) into electric power. Water leaves the turbine in the form of a two-phase flow like a mist, composed dominantly of steam but mixed with some carried liquid water droplets [18]. To allow reusing the exhaust water leaving the turbine, a condenser is needed to change the phase of any water vapor into saturated liquid, which can be sent to the pump.…”

Distribution Characteristics of High Wetness Loss Area in the Last Two Stages of Steam Turbine under Varying Conditions

“…In [16], condensation loss was analyzed from two aspects: multi-dispersed droplets and cascade trailing edge reduction. To reduce the condensation loss, the idea of turbulent flow disturbance on the suction side to reduce the liquid phase fraction was proposed in reference [17], and reference [7] took the initiative of injecting droplets.…”