.png)
Benchmark’s Advanced Propellants Development Lead, Sanil John, Ph.D., is no stranger to Computer Aided Engineering (CAE) tools. Our team utilizes a toolbox of analysis methodology to further our expertise in non-toxic propellants, including high-test peroxide, government-developed ASCENT, cold gas, and a range of solid metal propellants.
Sanil John, Ph.D., Advanced Propellants Development Lead
According to Sanil, “CAE tools provide our design and test engineers with key insights to enable faster design iterations and test campaigns. Since CAE tools are designed to handle specific types of physics, we can integrate the results from one CAE tool with another to effectively model multiphysics problems.” For example, Sanil partnered with colleagues Ben Tillotson, Lead Analysis Engineer and Matt Plumer, Design Engineer, to develop a procedure to integrate the profile of a surface property obtained from thermal analysis to a Computational Fluid Dynamics (CFD) tool as boundary condition.
The Benchmark team uses CFD to study performance of atomizers for use in its chemical propulsion thrusters. Liquid spray and fine droplets generated by a swirl atomizer and its heating upon contact with hot walls is discussed as a representative case. The figure alongside shows the initial wall temperature of the atomizer and the connected chamber, which are assigned temperature profiles. These profiles can be obtained from thermal analysis or interpolated from test data points. The walls are assigned heat flux to simulate the use of an electric heater.
The CFD model can simulate the formation of spray structure as well as the heating of the fluid as it flows through the atomizer and into the chamber. The formation of a spray begins with the inception of an air core in the swirl chamber, followed by liquid sheet formation and its thinning, and eventually a hollow cone structure is seen at the exit of the atomizer. In addition to the shape of the spray, measurements related to the dimensions and the angle of spray cone can be derived. Flowdata for most atomizers is usually only available for standard fluids, such as water. CFD models can be used to determine flow characteristics of atomizers for novel propellants to augment test data.
As the liquid flows through the swirl atomizer and the chamber, its temperature can also be determined using the CFD model. Such information is essential in designing for thermally activated energetic fluids such as propellants. The model can be extended to obtain droplet size distribution and other droplet properties such as temperature, velocity, residence time, etc. Such information is helpful in studying the interaction of the atomized spray with other flow media or solid surfaces as well as mixing, heating, and decomposition of propellants. 
The collaborative CAE work enables our propulsion team to drive significant performance enhancements and accelerate the development of our thrusters. The data also empowers our mission partners to make critical design decisions, reducing cost, easing integration, and improving mission success for our partners.
Additional Resources:
- Check out our Company page for additional in-house capabilities performed by our expert team.
- For details regarding Thruster specifications download the Thruster Data Sheet.
- For more thruster testing highlights, check out Benchmark Team Performs Simultaneous Bi-Coastal Hotfire Testing.