Modeling near critical and supercritical fuel injection and mixing in gas turbine applications

Claudio Lettieri, G. Subashki, Zoltan Spakovszky

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

Abstract

This paper presents a numeric al framework for characterizing fuel injection in modern combustors. The approach utilizes scaling analysis to describe the dro plet evaporation in non - dimensional and fluid - independent terms. The results of the model are validated against published experimental data of isolated droplets evaporating at subcritical and near - critical conditions. The model is incorporated in a spray c alculation framework and extended to the supercritical regime to assess the impact of different fluid - properties and evaporation models on temperature and fuel vapor distributions. The results suggest that in a non - convective environment the transient and quasi - steady evaporation rates vary exponentially with Lewis number. Furthermore, the results show fluid - independent behavior of the droplet evaporation, indicating that a single - component fluid can potentially be used as a modeling surrogate for jet fuel . The first - principles analysis demonstrates that classical evaporation models overestimate transient evaporation and underestimate quasi - steady evaporation, with discrepancies up to 70% at supercritica l conditions. This is due to limitations in fuel - prope rty description and the lack of non - isothermal droplet characterization at near - critical conditions. The temperature profiles are typically under - predicted and fuel vapor concentrations are over - predicted in standard spray calculations with subcritical eva poration models. As such the proposed framework breaks new ground in modeling of supercritical fuel injection. The improved quality in the predicted fuel concentration and temperature distribution can enable more accurate assessment of flame position, impr oving the estimation of combustion stability margins and NOx emissions. The model can be incorporated in commercial codes to guide the design of combustors operating at supercritical conditions.
Original languageEnglish
Title of host publicationASME 2018 Turbo Expo Turbomachinery Technical Conference & Exposition
Subtitle of host publicationJune 11-15, 2018, Oslo, Norway
Number of pages15
Publication statusPublished - 2018
Externally publishedYes
EventASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018: Turbomachinery Technical Conference and Exposition - Norway Exhibition and Convention Centre, Oslo, Norway
Duration: 11 Jun 201815 Jun 2018
Conference number: 63
https://www.asme.org/events/turbo-expo

Conference

ConferenceASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018
CountryNorway
CityOslo
Period11/06/1815/06/18
Internet address

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