Experimental tests were conducted to determine the electrical charge related deposition on turbine blades in a hot gas stream. Transpiration air cooled, water cooled, and uncooled turbine specimens were tested.
The results indicate that the gas stream charge is proportional to fluid particle velocity and particle concentration. The ionic concentration of the gas increases with increase in gas temperature in the range of 1000°F (537°C) to 2200°F (1200°C). The deposition was found to be less for the transpiration air cooled test sample at 1300°F (704°C) metal temperature and the excessively water cooled test sample at 350°F (176°C) than for the uncooled test samples. There is some evidence to indicate that by using electrostatic means, a reduction in deposition on turbine blades operating on a contaminated stream resulting from coal firing, may be possible.