RANS and LES Modeling of the GE10 Burner

The paper presents 1) the numerical results of RANS (Reynolds Averaging Navier-Stokes) simulations for two versions of the premixed combustion GE10 burners: the old one with non-premixed and modified one with swirled premixed pilot flames;and 2) the numerical results of joint RANS/LES (Large Eddy Simulation) modelling of the ONERA model burner and a simplified GE10 combustor. The original joint RANS/LES approach is based on using the Kolmogorov theory for modelling sub-grid turbulence and combustion intensity and using RANS numerical results for closure the LES model equations. The main conclusion is that developed joint RANS/LES approch is the efficient timesaving tool for simulations both the average and instantaneous fields of parameters in gas turbine and boiler burners with premixed combustion.

Measurements of Non-reacting and Reacting Flow Fields of a Liquid Swirl Flame Burner

The understanding of the liquid fuel spray and flow field characteristics inside a combustor is crucial for designing a fuel efficient and low emission device.Characterisation of the flow field of a model gas turbine liquid swirl burner is performed by using a2-D particle imaging velocimetry（PIV）system.The flow field pattern of an axial flow burner with a fixed swirl intensity is compared under confined and unconfined conditions,i.e.,with and without the combustor wall.The effect of temperature on the main swirling air flow is investigated under open and non-reacting conditions.The result shows that axial and radial velocities increase as a result of decreased flow density and increased flow volume.The flow field of the main swirling flow with liquid fuel spray injection is compared to non-spray swirling flow.Introduction of liquid fuel spray changes the swirl air flow field at the burner outlet,where the radial velocity components increase for both open and confined environment.Under reacting condition,the enclosure generates a corner recirculation zone that intensifies the strength of radial velocity.The reverse flow and corner recirculation zone assists in stabilizing the flame by preheating the reactants.The flow field data can be used as validation target for swirl combustion modelling.

Flame Morphology and Characteristic of Co-Firing Ammonia with Pulverized Coal on a Flat Flame Burner

Ammonia as a new green carbon free fuel co-combustion with coal can effectively reduce CO_(2)emission,but the research of flame morphology and characteristics of ammonia-coal co-combustion are not enough.In this work,we studied the co-combustion flame of NH_(3)and pulverized coal on flat flame burner under different oxygen mole fraction(X_(i,O_(2)))and NH_(3)co-firing energy ratios(E_(NH_(3))).We initially observed that the introduction of ammonia resulted in stratification within the ammonia-coal co-combustion flame,featuring a transparent flame at the root identified as the ammonia combustion zone.Due to challenges in visually observing the ignition of coal particles in the ammonia-coal co-combustion flame,we utilized Matlab software to analyze flame images across varying E_(NH_(3))and X_(i,O_(2)).The analysis indicates that,compared to pure coal combustion,the addition of ammonia advances the ignition delay time by 4.21 ms to 5.94 ms.As E_(NH_(3))increases,the ignition delay time initially decreases and then increases.Simultaneously,an increase in X_(i,O_(2))results in an earlier ignition delay time.The burn-off time and the flame divergence angle of pulverized coal demonstrated linear decreases and increases,respectively,with the growing ammonia ratio.The addition of ammonia facilitates the release of volatile matter from coal particles.However,in high-ammonia environments,oxygen consumption also impedes the surface reaction of coal particles.Finally,measurements of gas composition in the ammonia-coal flame flow field unveiled that the generated water-rich atmosphere intensified coal particle gasification,resulting in an elevated concentration of CO.Simultaneously,nitrogen-containing substances and coke produced during coal particle gasification underwent reduction reactions with NO_(x),leading to reduced NO_(x)emissions.

套管式燃气辐射管外壁平均温度的计算

套管式燃气辐射管外壁平均温度的计算刘存芳，周强泰张梦珠，华峰（东南大学动力工程系，南京２１００１８）（山东工业大学动力系，济南２５００１４）近几年来，套管式燃气辐射管已开始在我国工业生产中应用，其结构如图１所示，它主要由燃气燃烧器和内外套管组成。燃气...

Numerical Simulation of Gas-particle Flows with Different Swirl Numbers in a Swirl Burner

Swirl burner design was optimized by simulating swirl gas\|particle flows with different swirl numbers at the exit of a small\|scale swirl burner for pulverized\|coal furnaces using the k\|ε\|k p model. The predicted two\|phase time\|averaged velocities and particle concentration distributions for several different cases were compared to improve the design. The effect of the swirl number on the two\|phase velocities and particle concentration was investigated. The results give the two\|phase axial and tangential time\|averaged and fluctuation velocities and particle concentrations, showing that large recirculation zones of gas and particles forms in the near\|axis region of the burner exit, but the particle concentration in the recirculating zone is very low.

Cold Gas-particle Flows in a New Swirl Pulverized-coal Burner by PDPA Measurement

A new type of swirl burner has been developed to stabilize pulverized\|coal combustion by burning different types of coal at different loads and to reduce NO x formation during combustion. The burner uses a device to concentrate the coal powder in the primary\|air tube that divides the primary coal\|air into two streams with different pulverized\|coal concentrations. This paper reports the measurement of gas\|particle flows at the exit of the different swirl burners using a 3\|D Phase Doppler Particle Anemometer (PDPA). The effect of different geometrical configurations on the two\|phase flow field is studied. The results that give the two\|phase flow fields and particle concentrations show the superiority of the new swirl burner.

Numerical Simulation of a Batch-Type Reheating Furnace

A numerical analysis of a batch-type reheating furnace with and without thermal load was carried out using the Computational Fluid Dynamics technique. The furnace has two premixed burners and methane is used as fuel. Previous to the numerical experiments, a mesh convergence test was carried out and the average internal furnace temperature and the exhaust gases temperature were monitored as function of the number of cells in the discretized system. The influence of the Air/Fuel ratio, the position of the burners, and the thermal load on the average internal temperature, the exhaust gases temperature, and the molar fraction of methane and oxygen in the exhaust gases was numerically explored.

A Simplified Chemical Reaction Mechanism for Surrogate Fuel of Aviation Kerosene

n-Decane was chosen as a one-component surrogate fuel to investigate the combustion performance ofRocket Propellant-3（RP-3） aviation kerosene. Sensitivity analysis and the reaction-path mlalysis method were used tosimplify the detailed reaction mechanism of n-decane, and a simplified mechanism including 36 species and 62 ele-mentary reaction steps was obtained. Moreover, 38-step elementary reaction investigated in the reference was simu-lated in the paper. Numlerical simulation method was conducted for both the 62-step and the 38-step reaction me-chanisms using pre-evaporation combustion models. Simultaneously Bunsen bunter for the combustion of premixed,pre-evaporated RP-3 aviation kerosene was designed to verify the simplified mechanism, and the temperature and gascomponent concentrations in the axial and radial directions at different heights were measured. The experimental re-sults revealed that the reaction temperature and the CO2 concentration increased first and then decreased across thea：,：ial positions, but on the contrary for the O2 concentration. The temperature and the O2 concentration distributionsof experimental results are in good agreement with that of numerical simulation results for the 62-step simplifiedreactions, and the CO2 concentration distribution is in general agreement with the numerical data. But the 38-stepsimplified reactions can only predict the change trend for the important parameters which are mentioned above.Through the contrastive analysis for these two kinds of simplified reactions, the 62-step reactions can more accuratelysimulate the combustion characteristics of RP-3 kerosene. Aud n-decane can be used as a one-component surrogatefuel for RP-3 aviation kerosene.

Exergy-energy analysis of full repowering of a steam power plant

A 320 MW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowering methods. The power plant repower- ing has been analyzed for three different feed water flow rates： a flow rate equal to the flow rate at the condenser exit in the original plant when it works at nominal load, a flow rate at maximum load, and a flow rate when all the extractions are blocked. For each flow rates, two types of gas turbines have been examined： V94.2 and V94.3A. The effect of a duct burner has then been investigated in each of the above six cases. Steam is produced by a double- pressure heat recovery steam generator （HRSG） with reheat which obtains its required heat from the exhaust gases coming from the gas turbines. The results obtained from modeling and analyzing the energy-exergy of the original steam power plant and the repowered power plant indicate that the maximum efficiency of the repowered power plant is 52.04%. This maximum efficiency occurs when utilizing two V94.3A gas turbines without duct burner in the steam flow rate of the nominal load.