Primary Atomization Development- 2013

Project: Research project

Project Details

Description

Primary Atomization Development- 2013 Primary Atomization Development- 2013 Scope Although airblast atomizers are a common injector design in gas turbine engines and have been extensively studied experimentally for decades, the details of the initial, primary atomization of the injected liquid under relevant operating conditions are for the most part not well understood. This is in part due to the fact that optical access to the primary atomization region is often blocked by geometrical features of the injector and/or huge numbers of atomized drops shrouding the central liquid core. As a consequence, models describing the outcome of primary breakup, i.e. drop size, position, and momentum distributions required as input for secondary atomization/evaporation/mixing/combustion models often rely on empirical correlations requiring extensive experimental data matching. The proposed work addresses this crucial shortcoming in the gas turbine combustor modeling process. A prior Honeywell/ASU project developed a simulation tool to perform detailed simulations of the primary atomization region of airblast atomizers under operating conditions of interest to Honeywell. The tool consists of the flow solver FLUENT, coupled using Fluent UDFs to a level set interface tracker (LIT) based on the Refined Level Set Grid (RLSG) method developed at ASU. In this approach, the phase interface geometry and motion is resolved on a separate, high resolution grid, coupled to the unstructured Fluent flow solver that maintains the phase interface as a material discontinuity. To make the simulation of the atomization process generating hundreds of thousands of drops feasible, a multi-scale coupling procedure is employed by removing broken-off, small scale, nearly spherical liquid structures from the tracked level set representation and inserting them as Lagrangian point particles into Fluents DPM spray model thereby generating spray drop databases that can also be used for subsequent full combustor simulations. This simulation tool has so far been used to successfully simulate a rotationally periodic sector of a Honeywell airblast atomizer under one relevant operating condition. Results from this prior Honeywell/ASU project have identified areas, where the simulation tool can be improved to enable a more efficient use at Honeywell. These areas include: 1. Improve LIT and Fluent/LIT coupling efficiency by restricting the LIT solution domain to the periodic sector solved in Fluent; 2. Improve Fluent/LIT coupling memory efficiency by enabling dynamic memory allocation for coupling variables; this will enable faster overall coupling, since more data can be computed once and stored as look-up instead of having to be recomputed at every time step; 3. Enhance the Fluent UDF and LIT library to allow simulation of different cases/geometries without the need to recompile; 4. Validate the toolset on a second operating condition.
StatusFinished
Effective start/end date1/3/1311/15/13

Funding

  • INDUSTRY: Domestic Company: $50,000.00

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