Numerical Investigation of Impact of Relative Humidity Condition on Droplet Accumulation and Film Cooling on Compressor Blades

In this study, the relationship between the inlet relative humidity (RH) condition, heat transfer, and droplet accumulation/motions on gas turbine’s compressor blades involved in enhanced film cooling was investigated. Wet compression has gained popularity as a highly effective way to increase power output for gas turbine systems due to its simple installation and low cost. This process involves injection of droplets into the continuous phase (air with high temperature) of the compressor to reduce the temperature of the flow leaving the compressor and in turn increase the power output of the whole gas turbine system. This study focused on a single stage rotor-stator compressor model; the simulations are carried out using the commercial CFD tool ANSYS (FLUENT). In particular, the study modeled the interaction between the two phases including mass and heat transfer, given different inlet relative humidity (RH) and temperature conditions. The Reynolds Averaged Navier-Stokes (RANS) equations with k–ϵ turbulence model were applied as well as the droplet coalescence and droplet breakup model considered in the simulation. The interaction between the blade and droplets was modeled to address all possible interactions, which include: stick, spread, splash, or rebound. The goal of this study is to quantify the relationship between the RH and the overall heat transfer coefficient, and the temperature on the blade surface.