Effects of spray characteristics on combustion performance of a liquid fuel spray in a gas turbine combustor

Abstract

Spray characteristics like mean drop diameter and spray cone angle play an important role in the process of combustion within a gas turbine combustor. In order to study their effects on wall and exit temperature distributions and combustion efficiency in the combustor, a numerical model of a typical diffusion controlled spray combustion in a can‐type gas turbine combustion chamber has been made. A simple k–ϵ model with wall function treatment for near‐wall region has been adopted for the solution of conservation equations in carrier phase. The initial spray parameters are specified by a suitable PDF for size distribution and a given spray cone angle. A radiation model for the gas phase, based on modified first order moment method, and in consideration of the gas phase as a grey absorbing–emitting medium, has been adopted in the analysis. It has been recognized that an increase in mean drop diameter improves the pattern factor. However, the combustion efficiency attains its maximum at an optimum value of the mean diameter. Higher spray cone angle increases the combustion efficiency and improves the pattern factor, but at the same time, increases the wall temperature. Copyright © 1999 John Wiley & Sons, Ltd.

Large Deviation Analysis of a Droplet Model Having a Poisson Equilibrium Distribution

“…we use the sequence ( ) in (17), which converges weakly to . We conclude that lies in the closure of P N , and thus that P N , [ , ] is a subset of the closure of P N , in P N .…”

“…The importance of predicting droplet size can be seen from the wide range of applications utilizing sprays [17,18]. Because of the importance of this problem, novel approaches for measuring size distribution of droplet size in sprays have been developed [19][20][21][22][23].…”

Effect of Combustor Geometry on Performance of Airblast Atomizer Under Sub-Atmospheric Conditions

“…Results show a wide broadening of the droplet size distribution and SMD when compared to idle. Since most of the fuel is within the larger droplets, the evaporation rate decreases, causing a slower combustion reaction and a reduction in combustion efficiency (Datta and Som, 1999;Lefebvre;1985, Lefebvre, 1998. Beck et al (1989), as shown in Fig.…”

“…An in-flight shutdown can occur due to an engine malfunction, external factors (such as volcanic ash) or a deliberate shutdown by the pilot. However, for each scenario, the chamber conditions (temperature, pressure and air velocity), chamber volume, and spray characteristics (Datta and Som, 1999;Lefebvre, 1985; Lefebvre, 1998) greatly determine the relight and pull-away capability of the engine. A useful unit of measurement in terms of spray quality is the Sauter Mean Diameter (SMD), defined as the droplet diameter which has the same volume to surface area ratio as that of the whole spray.…”

Numerical Investigation on the Effects of Inlet Air Temperature on Spray Combustion in a Wall Jet Can Combustor Using thek − ε Turbulence Model

“…Datta and Som [16] also used the k À e turbulence model to examine the effect of spray cone angle and drop diameter on wall and exit temperature distributions and combustion efficiency in the combustor. The eddy break-up (EBU) combustion model was used to analyze the burning of n-hexane (C 6 H 14 ) fuel in their study.…”