Influence of Turbulence Schmidt Number on Exit Temperature Distribution of an Annular Gas Turbine Combustor using Flamelet Generated Manifold

2019 ◽  
Vol 29 (1) ◽  
pp. 58-68
Author(s):  
Weihao Wang ◽  
Songlin Yang ◽  
Chuang Gao ◽  
Weiguang Huang
Author(s):  
P. J. Vermeulen ◽  
J. Odgers ◽  
V. Ramesh

A small combustor of normal design employing acoustic control of the dilution-air flows has been successfully tested up to “half-load” conditions. It has been shown that this technique can be used to selectively and progressively control the exit plane temperature distribution, and the ability to trim the temperature profile has been convincingly demonstrated. The acoustic driver power requirements were minimal indicating that driver power at “full-load” will not be excessive. The nature of the acoustically modulated dilution-air flows has been clearly establish to the design of combustors such that a desired exit plane temperature distribution may be achieved.


2012 ◽  
Vol 510 ◽  
pp. 545-548
Author(s):  
Liang Yu ◽  
Shu Sheng Yuan ◽  
Zhi Bing Pang ◽  
Yun Liang Wang

RNG (Renormalization Group) k-ε turbulent model was applied to the numerical simulation of turbulent mixing processes in the RQL gas turbine combustor, and SIMPLE algorithm was used to solve the finite difference equations. The calculated conclusions were used to analyze temperature distribution of the mixed flow field and near-wall region of the flow field, and then discuss the NOx emissions. The results show that the effect of the injector zone geometry and the jet to crossflow momentum flux ratios on the NOx emissions is obvious. The reasonable control of jet is beneficial to reduce the local high temperature area and is able to improve the distribution of the exit temperature. And then achieve the goal of reducing the environmental pollution.


1977 ◽  
Vol 99 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D. Kretschmer ◽  
J. Odgers ◽  
A. F. Schlader

A mechanically pulsed suction thermocouple has been developed. The gas to be measured is sucked through a sonic orifice, thus eliminating the influence of the velocity inside the combustor. The signal from the thermocouple is processed by an analogue circuit. Contrary to the usual approach to the problem of dynamic temperature measurements (i.e., the attempt to find an exact solution to the extrapolation of the temperature rise curve) in this work, a calibration of the probe was done. This calibration showed very little scatter and a good repeatability. The overall measurement accuracy was better than ±1 percent. As a test of application, a partial survey of the temperature distribution within an aircraft gas turbine combustor was done. A satisfactory agreement was observed between temperatures measured by the thermocouple and those determined from gas analysis. In this test the pulse thermocouple proved to be a reliable and fast tool for the measurement of local gas temperatures.


2015 ◽  
Vol 32 (2) ◽  
Author(s):  
R. K. Mishra ◽  
S. Kishore Kumar ◽  
Sunil Chandel

AbstractLean blow out characteristics in a swirl stabilized aero gas turbine combustor have been studied using computational fluid dynamics. For CFD analysis, a 22.5° sector of an annular combustor is modeled using unstructured tetrahedral meshes comprising 1.2 × 10


2021 ◽  
Author(s):  
Saurabh Patwardhan ◽  
Pravin Nakod ◽  
Stefano Orsino ◽  
Rakesh Yadav ◽  
Fang Xu ◽  
...  

Abstract Carbon monoxide (CO) has been identified as one of the regulated pollutants and gas turbine manufacturers target to reduce the CO emission from their gas turbine engines. CO forms primarily when carbonous fuels are not burnt completely, or products of combustion are quenched before completing the combustion. Numerical simulations are effective tools that allow a better understanding of the mechanisms of CO formation in gas turbine engines and are useful in evaluating the effect of different parameters like swirl, fuel atomization, mixing etc. on the overall CO emission for different engine conditions like idle, cruise, approach and take off. In this paper, a thorough assessment of flamelet generated manifold (FGM) combustion model is carried out to predict the qualitative variation and magnitude of CO emission index with the different configurations of a Honeywell test combustor operating with liquid fuel under idle condition, which is the more critical engine condition for CO emission. The different designs of the test combustor are configured in such a way that they yield different levels of CO and hence are ideal to test the accuracy of the combustion model. Large eddy simulation (LES) method is used for capturing the turbulence accurately along with the FGM combustion model that is computationally economical compared to the detailed/reduced chemistry modeling using finite rate combustion model. Liquid fuel spray breakup is modeled using stochastic secondary droplet (SSD) model. Four different configurations of the aviation gas turbine combustor are studied in this work referring to earlier work by Xu et al. [1]. It is shown that the FGM model can predict CO trends accurately. The other global parameters like exit temperature, NOx emissions, pattern factor also show reasonable agreement with the test data. The sensitivity of the CO prediction to the liquid fuel droplet breakup model parameters is also studied in this work. Although the trend of CO variation is captured for different values of breakup parameters, the absolute magnitude of CO emission index differs significantly with the change in the values of breakup parameters suggesting that the spray has a larger impact on the quantitative prediction of CO emission. An accurate prediction of CO trends at idle conditions using FGM model extends the applicability of FGM model to predict different engine operating conditions for different performance criteria accurately.


Author(s):  
K. Sudhakar Reddy ◽  
D. N. Reddy ◽  
C. M. Vara Prasad

An experimental work was carried out on confined swirling flows under non-combusting conditions in a reverse flow annular gas turbine combustor. Flow measurements with a five hole pitot probe are carried out in a flow apparatus of a geometrical configuration similar to the model of a swirl combustor. Mean flow results are obtained for different flow conditions to determine the effect of swirl on the recirculation zone and the variation of the swirl strength along the axis of the gas turbine combustion chamber. The boundaries of the recirculation region are plotted to compare the size and length of the zone with various swirlers. Minimum flow Reynolds number is required for flow recirculation; the effect of Reynolds number on determining which flow class is present for flow of interest in combustion chamber was investigated. The inlet swirl number is optimized for higher swirl strength and the inlet swirl number for which recirculation completely vanishes is also estimated.


Author(s):  
Wei Dai ◽  
Yuzhen Lin ◽  
Quanhong Xu ◽  
Chi Zhang ◽  
Xin Xue

The exit temperature distribution had a great effect on reliability and security in a gas turbine. In this paper, the exit temperature distribution of a small engine reverse-flow combustor with three injectors test module was experimentally obtained to qualitatively analyze the influence of the primary zone operating condition by changing the fuel air ratio at the ambient pressure and temperature condition. Under the nearly identical air condition, there was no obvious difference on the mixing performance with different fuel flow rate. The hot zones occurred at the same position of the combustor exit section, and the temperature declined in the radial direction from the center. It could be seen that the radial temperature profiles in FAR of 0.022–0.03 were almost same. Malvern experimental results showed that the air fuel ratio of swirler cup ranges from 5 to 40 and the droplet distribution index n could not be increased or decreased by the ratio at different air pressure drop. The air fuel ratio of combustor swirl cup had reached more than 5 which fuel particle had been nearly stable and not got some variation by changing the fuel mass rate. As a result, the increase of fuel air ratio had no impact on fuel atomization uniformity in combustor dome. The fuel had been completely atomized when the combustor fuel air ratio ranged from 0.022 to 0.03, and its impact on the droplet size and uniformity of fuel could be neglected. With the uniform fuel spray, a numerical study of the whole combustor had been made to analyze the strong relation between swirl flow and jets of primary holes and dilution holes. The dilution jets had a strong effect on quenching flame and temperature dilution. Along the combustor flow direction, the temperature difference became less and less obvious, the addition of fuel would enhance the combustion intensity mainly in combustion zone, but with an effect of dilution jet, the temperature distributions had little deviation when increasing the fuel air ratio. And it showed a same phenomenon that different fuel air ratio would make the same exit temperature distribution which was found to be in line with the experimental results. In a word, for the primary zone operating condition in the combustor, it almost had no effect on the temperature distribution at the exit of the combustor by changing the fuel air ratio from 0.022 to 0.030 in primary zone at normal pressure and temperature condition.


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