Collaborative Proposal: Discoveries in multiphase detonations: Fuel droplet processing at extreme conditions

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Combustion of storable, liquid fuels is common in everyday life, powering cars, trains, airplanes, and ships. The combustion efficiency in these engines depends on the reaction rate. As the reaction rate becomes faster, the combustion front propagates faster and can exceed the speed of sound, in a process known as a detonation wave. Combustion devices operating with detonation waves can yield much higher efficiencies compared to traditional engines. In liquid fueled detonation engines, fuel droplets, about the size of a red blood cell, must be broken up, evaporated, and reacted over few nanoseconds. In this project, a combination of new experimental and simulation methods will be used to better understand liquid fuel break up process and to develop a new model for the burning of fuel droplets in a detonation wave. The model developed can be used to improve the design of engines for civilian and defense applications. The overall goal of this project is to understand how 2-20 nanometer fuel droplets undergo simultaneous hydrodynamic breakup, vaporization, and reaction (SBVR) under detonation conditions. For this purpose, a new SBVR model will be developed and tested with fully resolved microscale simulations, and mesoscale multiphase detonation tube experiments and simulations. Microscale simulations will be performed using an in-house simulation code, IMPACT, based on the ghost fluid method. The SBVR model will be implemented on Lagrangian point particles in the open source hydrodynamics code, FLASH to simulate mesoscale experiments. Experiments will be conducted using the multiphase detonation tube facility. The key tasks to be conducted include, (i) investigations of simultaneous droplet breakup, phase change, and reaction in microscale simulations; (ii) measurement of detonation properties for various fuel droplet sizes using detonation tube experiments; and (iii) development and testing the SBVR model using experimental and mesoscale simulations data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.