Advanced additive manufacturing opens new ways to improve gas turbine fuel nozzles to enhance engine durability and performance while reducing gas emissions including NOX, CO, and Soot. Additively building complex fuel passages enables engineers to better control the fuel-air mixing and its burning, not only in gas-only but also in dual fuel engine configurations. Dual fuel engines have additional requirements for proper liquid jet trajectory and spray quality that needs to be met through the careful injector configuration within the liquid fuel cartridges. Additionally, liquid fuel cartridges in the combustor are consolidated into one cartridge with a set of discrete injectors in near proximity for cost benefits, which leads to complex multi-fuel injector designs. This can be an engineering challenge during the engine development because the traditional specifications for spray characterization (that are based on classical correlations for single jet in crossflow) don't necessarily hold true for multiple discrete jets. In addition, the flow approaching the discrete jets is not uniform in recent combustor architectures. Spray characteristic of multiple liquid jets in crossflow is very different from a single jet's behavior, primarily due to axial shadowing effects and lateral jet-to-jet interactions. This paper highlights the main differences in droplet sizes and jet trajectories based on the experiments conducted at University of Cincinnati Research Institute (UCRI), as well as comparable CFD results performed at General Electric Combustion Engineering. The shadowing effect will result in larger droplet sizes that can significantly impact the combustion performance. The fundamental physics and understanding of these interactions can help the combustor engineers to specify liquid fuel injectors that provide a suitable spray quality for flame stabilization in gas turbine engines. 

Numerical Modeling of Multiple Liquid Jets in Crossflow for Gas Turbine Spray Characterization


 One of the most used spray configurations for gas turbines and power combustors is liquid jet in crossflow. The process of breakup of liquid jet is very complex and understanding this mechanism is of paramount importance in engine design. This has led to the commencement of several studies from leading research groups [1–6]. Several new modeling methods such as the Madabhushi breakup model or more detailed VOF and Level set methods have been used successfully to understand and describe these complex breakup processes. However, most of these studies have been restricted to liquid jet in uniform single stream crossflow. In reality, these jets could be subjected to several gaseous streams and the breakup mechanism may vary significantly. Recently there have been some studies to understand the effect of non-uniformities on the crossflow velocity distribution and the droplet diameter. In the current work, we attempt to extend the scope of the Madabhushi breakup model to jets subjected to non-uniform crossflow. Non-uniform crossflow is created by co-directional and parallel gas flow using several hollow tubes. Locally, the momentum flux ratio changes by a factor of 4 and uniformity ratio (the ratio of the velocities of the two gas streams) of 2. A modified version of the Madabhushi model as proposed by Lambert et. al is used here to simulate the jet breakup. Model tuning has been conducted using University of Cincinnati Research data specifically designed for this configuration in partnership with General Electric Company. For turbulence, realizable k-ε with scalable wall function is used. The droplets are tracked using Ansys Fluent Discrete Particle Model (DPM). A second modeling approach VOF-to-DPM is also used which uses VOF equation along with LES with Dynamic Kinetic Energy Subgrid-Scale Model. This model requires no fine tuning of parameters and is more accurate but comes with more computational expense.
 Various simulations are performed with pure water, pure diesel and emulsified diesel and water with uniform and non-uniform cross flows inside a chamber at a pressure of 50psi. Overall, the trends due to difference in material properties of the two liquids especially on penetration and Sauter mean diameter are well captured. The droplet characteristics such as axial velocity, Sauter mean diameter and volumetric flux are compared with experimental measurements and shows reasonable agreement. Overall, the liquid penetration is within reasonable accuracy. Discrepancies were seen in the spatial variation of the spray quantities such as Sauter mean diameter, droplet axial velocity etc. The simulation revealed a more averaged field whereas in experiments some layering was observed with bigger droplets at the edge of the spray, away from the wall.

Numerical Modeling of Liquid Jet in Non-Uniform Crossflow Using Enhanced Madabhushi Model

As hydrogen is gaining popularity as an alternative source of energy, there is a strong focus on understanding the hazards related to its storage and transport. Nowadays, there are two means of transporting and storing hydrogen: in a liquid state or in a gaseous state at very high pressure. For the latter, the hydrogen is often stored in highly pressurized tanks, which could be subject to accidental damage and subsequent leakages. As hydrogen is highly flammable, the auto-ignition of leaked hydrogen may further cause a potentially serious safety hazard. The current work focuses on numerically predicting the auto-ignition patterns of suddenly released hydrogen from a pressurized tank into the atmosphere. The latest density-based CFD solver is utilized to simulate the 3D turbulent structures during the mixing of the fast-propagating hydrogen with the ambient air, using Large Eddy Simulation for turbulence and Finite Rate Chemistry for combustion. The mesh is automatically refined to capture the turbulent eddies, shock waves and thin reaction zones. The numerical calculations are performed at three tank pressures (250 bar, 100 bar and 50 bar) within two sector domains (1◦ and 30◦). The turbulent diffusion and auto-ignition patterns of the leaked hydrogen are correctly predicted across different operating conditions. 

Numerical Prediction of Pressurized Hydrogen Leakage and Spontaneous Ignition

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

V. Kumar

Author Tools

Chat about Author

Papers

Numerical Modeling of Liquid Jet in Non-Uniform Crossflow Using Enhanced Madabhushi Model

Numerical Prediction of Pressurized Hydrogen Leakage and Spontaneous Ignition

Numerical Modeling of Multiple Liquid Jets in Crossflow for Gas Turbine Spray Characterization