Effect of Mach number and equivalence ratio on the pressure rising variation during combustion mode transition in a dual-mode combustor

An experimental investigation was undertaken of the influence on emissions of full coverage discrete hole film cooling of a lean low NOx radial swirler natural gas combustor. The combustor used radial swirler vane passage fuel injection on the centre of the vane passage inlet. The test configuration was similar to that used in the Alstom Power Tornado and related family of low NOx gas turbines. The test conditions were simulated at atmospheric pressure at the flow condition of lean low NOx gas turbine primary zones. The tests were carried out at an isothermal flow Mach number of 0.03, which represents 60% of industrial gas turbine combustor airflow through the swirl primary zone. The effusion film cooling used was Rolls-Royce Transply, which has efficient internal cooling of the wall as well as full coverage discrete hole film cooling. Film cooling levels of 0, 16 and 40% of the primary zone airflow were investigated for a fixed total primary zone air flow and reference Mach number of 0.03. The results showed that there was a major increase in the NOx emissions for 740K inlet temperature and 0.45 overall equivalence ratio from 6ppm at zero film cooling air flow to 32ppm at 40% coolant flow rate. CO emissions increased from 25ppm to 75ppm for the same increase in film cooling flow rate. It was shown that the main effect was the creation of a richer inner swirler combustion with a surrounding film cooling flow that did not mix well with the central swirling combustion. The increase in NOx and CO could be predicted on the basis of the central swirl flow equivalence ratio.

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A control-oriented hybrid combustion model of a homogeneous charge compression ignition capable spark ignition engine

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407012443334 ◽

2012 ◽

Vol 226 (10) ◽

pp. 1380-1395 ◽

Cited By ~ 11

Author(s):

Xiaojian Yang ◽

Guoming G Zhu

Keyword(s):

Homogeneous Charge Compression Ignition ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Combustion Model ◽

Mode Transition ◽

Compression Ignition ◽

Combustion Mode ◽

Combustion Phase ◽

Compression Ignition Combustion ◽

Homogeneous Charge

To implement the homogeneous charge compression ignition combustion mode in a spark ignition engine, it is necessary to have smooth mode transition between the spark ignition and homogeneous charge compression ignition combustions. The spark ignition–homogeneous charge compression ignition hybrid combustion mode modeled in this paper describes the combustion mode that starts with the spark ignition combustion and ends with the homogeneous charge compression ignition combustion. The main motivation of studying the hybrid combustion mode is that the percentage of the homogeneous charge compression ignition combustion is a good parameter for combustion mode transition control when the hybrid combustion mode is used during the transition. This paper presents a control oriented model of the spark ignition–homogeneous charge compression ignition hybrid combustion mode, where the spark ignition combustion phase is modeled under the two-zone assumption and the homogeneous charge compression ignition combustion phase under the one-zone assumption. Note that the spark ignition and homogeneous charge compression ignition combustions are special cases in this combustion model. The developed model is capable of simulating engine combustion over the entire operating range, and it was implemented in a real-time hardware-in-the-loop simulation environment. The simulation results were compared with those of the corresponding GT-Power model, and good correlations were found for both spark ignition and homogeneous charge compression ignition combustions.

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Experimental Study of Test Medium Vitiation Effects on Dual-Mode Scramjet Mode Transition

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition ◽

10.2514/6.2010-1126 ◽

2010 ◽

Cited By ~ 8

Author(s):

Robert Rockwell ◽

Christoper Goyne ◽

Willie Haw ◽

Roland Krauss ◽

James McDaniel ◽

...

Keyword(s):

Experimental Study ◽

Mode Transition ◽

Test Medium ◽

Dual Mode

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Distributed parameter control arithmetic for an axisymmetrical dual-mode scramjet

The Aeronautical Journal ◽

10.1017/s0001924000002517 ◽

2008 ◽

Vol 112 (1135) ◽

pp. 557-565 ◽

Cited By ~ 13

Author(s):

C. Tao ◽

Y. Daren ◽

B. Wen

Keyword(s):

Control Theory ◽

Shape Control ◽

Distributed Parameter ◽

Mode Transition ◽

Dual Mode ◽

Transition Control ◽

Wide Range ◽

Mode Transition Control ◽

Control Arithmetic ◽

Smooth Transitions

AbstractDual-mode scramjet is one of the candidates for hypersonic flight propulsion system which will be used in wide range of flight Mach numbers from 4 to 12 or higher, wherein dual-mode scramjet should be well designed to be suitable for subsonic/supersonic combustion operation according to the flight conditions. Therefore this system is required to operate in a finite number of operational modes that necessitate robust, stable, and smooth transitions between them by which selective operability of supersonic/subsonic combustion modes and efficient combustor operation in these modes may be realised. A key issue in making mode transition efficient and stable is mode transition control. The major problem in mode transition control is the handling of the various flow and combustion coupling effects of dual-mode scramjet whose physical states are spatially coupled and whose governing equations are partial differential equations. Involving these distributed parameter issues, our basic idea is using the shape control theory to study the control problems of mode transition for dual-mode scramjet with the aim of achieving the desirable design properties and increasing control reliabilities. This specific approach is motivated by the promise of novel techniques in control theory developed in recent years. Concrete control arithmetic of this approach, such as shape control model, sensitivity analysis and gradient-based optimisation procedure, are given in this paper. Simulation results for an axisymmetric, wall-injection dual-mode scramjet show the feasibility and validity of the method.

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