Validation of under-resolved numerical simulations of the PDC exhaust flow based on high speed schlieren

M. Nadolski, M. Rezay Haghdoost, J. A.T. Gray, D. Edgington-Mitchell, K. Oberleithner, R. Klein

Research output: Chapter in Book/Report/Conference proceedingChapter (Book)Other

2 Citations (Scopus)

Abstract

Owing to their high thermodynamic efficiency, pulsating combustion cycles have become an attractive option for future gas turbine designs. Yet, their potential gains should not be outweighed by losses due to unsteady pressure wave interactions between engine components. Consequently, the geometric engine design moves into focus. Ideally, one would quickly test several different principal layouts with respect to their qualitative behavior, select the most promising variants and then move on to detailed optimization. Computational fluid dynamics (CFD) appears as the methodology of choice for such preparatory testing. Yet, the inevitable geometric complexity of such engines makes fully resolved CFD an arduous and expensive task necessitating computations on top high-performance hardware, even with modern adaptive mesh refinement in place. In the present work we look at the initial flow field of a shock generated by a pulse detonation combustor (PDC) which leaves the combustion chamber and enters the plenum. We provide first indicators, however, that overall mechanical loads, represented by large-scale means of, e.g., mass, energy, and momentum fluxes can be well estimated on the basis of rather coarsely resolved CFD calculations. Comparing high-resolution simulations of the exit of a strong shock from a combustion tube with experimental schlieren photographs, we first establish validity of fully resolved CFD. Next we compare several integral quantities representative of overall mechanical loads with a sequence of successively coarser grid simulations, thereby corroborating that the “quick and dirty” coarse-grained simulations indeed allow for good order of magnitude estimates.

Original languageEnglish
Title of host publicationNotes on Numerical Fluid Mechanics and Multidisciplinary Design
PublisherSpringer-Verlag London Ltd.
Pages237-253
Number of pages17
DOIs
Publication statusPublished - 1 Jan 2019
EventActive Flow and Combustion Control 2018 - Berlin, Germany
Duration: 19 Sep 201821 Sep 2018

Publication series

NameNotes on Numerical Fluid Mechanics and Multidisciplinary Design
Volume141
ISSN (Print)1612-2909

Conference

ConferenceActive Flow and Combustion Control 2018
CountryGermany
CityBerlin
Period19/09/1821/09/18

Keywords

  • Coarse resolution CFD code validation
  • Expansion from detonation tube
  • Experimental Schlieren visualization

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