Collaborative Research: Discoveries in Multiphase Detonations: Fuel Droplet Processing at Extreme Conditions

燃烧可储存的液体燃料在日常生活中很常见，为汽车、火车、飞机和轮船提供动力。这些发动机的燃烧效率取决于反应速率。随着反应速率的加快，燃烧锋面的传播速度也会加快，甚至可以超过声速，这一过程被称为爆震波。与传统发动机相比，利用爆震波工作的燃烧装置可以产生更高的效率。在液体燃料爆炸发动机中，红血球大小的燃料液滴必须在几纳秒内被分解、蒸发并发生反应。在这个项目中，将采用新的实验和模拟相结合的方法来更好地了解液体燃料的分解过程，并开发一个新的模型来研究燃料液滴在爆震波中的燃烧。该模型可用于改进民用和国防发动机的设计。该项目的总体目标是了解2-20纳米燃料液滴如何在爆轰条件下同时进行流体动力学破裂、汽化和反应（SBVR）。为此，将开发一种新的SBVR模型，并通过全分辨率微尺度模拟和中尺度多相爆轰管实验和模拟进行测试。微尺度模拟将使用内部模拟代码IMPACT进行，该代码基于鬼影流体方法。SBVR模型将在拉格朗日点粒子上实现，在开放源代码的流体力学代码FLASH中模拟中尺度实验。实验将使用多相爆轰管设备进行。关键任务包括：(1)微尺度模拟中液滴同时破碎、相变和反应的研究；（ii）利用爆震管实验测量不同尺寸燃料液滴的爆震特性；（iii）利用实验和中尺度模拟数据开发和测试SBVR模式。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.