Comprehensive Review on Numerical Simulation and Design Optimization of Valveless Pulsejet Engine.

The mechanical simplicity and the lack of moving parts of valveless pulsejet engines again fueled interest in using cost-effective forms of propulsion in aerospace propulsion (micro air vehicles (MAVs) and unmanned aerial vehicles (UAVs). This review describes the evolution of numerical simulation and design optimization with particular emphasis on historical performance, experimental work and current computational software such as ANSYS Fluent, and MATLAB. The high thrust to weight ratios of these engines are achieved through optimization of geometry (such as the size of the combustion chamber and exhaust piping) as well as ensuring the inlets facing backward in order to maximize static thrust. Computational Fluid Dynamics (CFD) and Large Eddy Simulation (LES) studies complex flow dynamics, acoustics, and chemical kinetics to increase the combustion efficiency and thrust of the plane, tackling the problem of unnecessary noise, or thermal inefficiencies. Among the innovations advancements that enhance stability and reduce noise include; flame holders, Helmholtz resonators and dual- intake systems; and thermally robust materials which include stainless steel and quartz glass. The thrust-specific fuel consumption of propane is (0.574 kg/N-h) better than that of gasoline meaning that there is the option of optimization of fuel. Both the performance enhancements by way of the golden section approach and acoustic delaying via plenum chambers happen. There are challenges in making them including as heat loss and vibration but the active control systems trend, hybrid propulsion and sustainable fuels have shown to be scalable and have longevity. Valveless pulsejets are powerful but lightweight propulsion systems that have come to form their own mini-industry with new development focused on pushing the limits through rigorous design simulations and material innovations.