PRIME: Unresolved fluid mechanics at liquid/gas interfaces for PRIMary brEakup of atomizing sprays
Lead Research Organisation:
University of Edinburgh
Department Name: Sch of Engineering
Abstract
Efficient spray atomization plays a critical role within society, ranging from effective medical treatment to cleaner propulsion systems. Primary breakup - the process of disintegrating a liquid stream into large (primary) drops - is the consequential first step of atomization, but is also the least understood for atomizing sprays. This long-standing problem exists due to a lack of experimental tools that can measure the fundamental fluid dynamics that govern the primary breakup processes at liquid-gas interfaces (LGI) at the core of the spray. PRIME is uniquely designed to address this problem. We have developed a unique set of advanced diagnostic tools that provide the exclusive capability to measure fluid velocity and acceleration at LGIs of the liquid jet and primary drops. These tools are a unique combination of pulse-burst Ballistic Imaging combined with wavelet-based Optical Flow (wOF). In PRIME, we establish our proof-of-concept tools, and develop wOF for original applications with two-photon laser induced fluorescence, to provide ground-breaking measurements that help resolve unanswered questions of primary breakup. Two spray facilities will be developed in PRIME, which provide a unique platform to apply our diagnostics for new fundamental knowledge for a range of sprays from basic to technically-relevant complex sprays. These facilities will include custom-built transparent nozzles to perform imaging measurements inside the spray nozzle. Advanced diagnostics will be combined with a suite of established imaging diagnostics (shadowgraphy, schlieren, micro-PIV) to correlate the primary breakup flow dynamics with its corresponding breakup genesis occurring inside the spray nozzle. PRIME will provide substantial breakthroughs in knowledge, and will generate a comprehensive spray database designed for the development and validation of computational models for the wider spray community. As such, PRIME is intended for long term success.
| Title | Development of wOFV approach for atomizing spray resarch |
| Description | We have developed a wavelet based optical flow velocimetry (wOFV) platform that enables us to study the unresolved fluid mechanics at liquid-gas interfaces. We have benchmarked this platform using ground truth data from DNS simulations, and this work is in the process of being disseminated to the research community. We have several research output journal submissions and we look forward to them soon being published. |
| Type Of Material | Technology assay or reagent |
| Year Produced | 2025 |
| Provided To Others? | No |
| Impact | Understanding the fluid mechanics of primary atomization has been difficult because we do not have the tools to study fluid dynamics and elongated interfaces. Particle image velocimetry is often the workhorse of experimental fluid mechanics, but is not designed to track velocities of elongated interfaces. We have developed a wavelet-based optical flow velocimetry platform, which can measure dense velocity fields (vector per pixel) along elongated interfaces. We have benchmarked our platform, and are now generating experimental data for novel studies of fluid mechanics at liquid-gas interfaces. |
| Description | Development of wavelet based optical flow for atomizing liquid sprays |
| Organisation | RWTH Aachen University |
| Country | Germany |
| Sector | Academic/University |
| PI Contribution | We are developing a wavelet based optical flow (wOF) platform for spray research. wOF provides the unique ability to measure velocity and acceleration of fluid particles at liquid/gas interfaces. Using this novel capability for elongated interfaces, we can now resolve the interfacial flow instabilities describing primary atomization. We are working with RWTH Aachen on this project. They are providing DNS data of a mildly atomizing spray to benchmark our wOF platform. This platform will then be used for experimental measurements, where ground truth data is not available. |
| Collaborator Contribution | We are the pioneers behind the wOF platform. |
| Impact | We have two conference papers that have been submitted and soon a journal article will be submitted. We expect many more papers to come out of this collaboration. |
| Start Year | 2024 |