Jet Characteristics of Pulsed Arc SparkJet Actuator and Performance Improvement with Dual-Spark Pulses

Performance characteristics of the jet produced by SparkJet actuator are investigated with a numerical simulation. The spark discharge is considered as a uniform heat source in energy equation modeled with a user-defined function in Fluent. The SparkJet actuator is tested with both single-spark pulse and dual-spark pulses. Validation with experiments for a single 50 mJ spark pulse shows that Joule heating factor for the heat source term is about 5%. Jet velocity increases and total impulse decreases with the distance of the spark from the exit orifice. Peak velocity and peak thrust increase with the volume of the spark discharge. Total impulse increases as the time delay between two temporally separated pulses increases. Spatially separated dual-spark pulses produce higher jet velocity as the time delay between the pulses increases. Performance testing of jets in various operating modes informs that the SparkJet actuator is more efficient and effective when spatiotemporally separated dual-spark pulses are turned on in downstroke operation with an adequate time delay between pulses.