CEAS Aeronautical Journal

, Volume 2, Issue 1, pp 111–123

Development and application of a pre-design tool for aero-engine combustors

Authors

    • German Aerospace Center DLRInstitute of Propulsion Technology
  • T. Behrendt
    • German Aerospace Center DLRInstitute of Propulsion Technology
Original Paper

DOI: 10.1007/s13272-011-0012-x

Cite this article as:
Tietz, S. & Behrendt, T. CEAS Aeronaut J (2011) 2: 111. doi:10.1007/s13272-011-0012-x

Abstract

A software tool was developed to design aero-engine combustors on a preliminary level. Only a small set of input parameters is required to design conventional as well as lean combustors. During the design calculation the combustor contour, the geometry of the desired cooling concept and the air flow distribution within the combustor are optimized. Optimization targets are to minimize the cooling air consumption with respect to the material temperature limits and to reach homogeneous material temperatures as well as a stable combustion. In the case of a staged burner the burner air and fuel fractions are optimized regarding minimal NOx production (qualitative) for the design condition. Off-design calculations on the basis of designed combustors can be executed for engine conditions other than take-off to calculate the altered conditions within the combustor. This paper shows the design and off-design process of the combustor tool in detail. In a second part application examples are given. The presented results show the capabilities of the tool for the pre-design of lean combustors with respect to the trade-off between the reduction of NOx emissions and the reduction of the fuel consumption as well as the capabilities for identifying potential cooling issues.

Keywords

Aero engineGas turbineCombustorPreliminary designEffusion cooling

List of symbols

cd

Discharge coefficient (–)

d

Diameter (m)

Ma

Mach number (–)

m = ρAiruAir/(ρGasuGas)

Blowing ratio (–)

p

Pressure (Pa)

Δpst

Static pressure drop (Pa)

Δpst,rel = Δpst/p3

Relative static pressure drop (–)

Rs

Specific gas constant (J/kg/K)

Re

Reynolds number (–)

r

Radius (m)

s

Slot height (m)

T

Temperature (K)

t

Thickness (m)

u

Velocity (m/s)

V

Volume (m3)

W

Mass flow (kg/s)

μ

Dynamic viscosity (Ns/m2)

ρ

Density (kg/m3)

φ

Empirical factor (–)

Subscripts

C

Combustor

Cond

Conduction

Conv

Convection

Eff

Effusion

Rad

Radiation

Stoich

Stoichiometric

Up

Upstream

3

Condition upstream the combustor

4

Condition downstream the combustor

Copyright information

© Deutsches Zentrum für Luft- und Raumfahrt e.V. 2011