旋转流线涡技术对驻涡燃烧室性能的影响

基于凹腔驻涡燃烧室的基本结构,提出了一种新的燃烧流场组织技术———旋转流线涡技术,并通过数值模拟,对比分析了不同进气条件下该技术与传统驻涡燃烧技术对燃烧室涡及燃烧性能的影响。结果表明:与传统驻涡燃烧室相比,旋转流线涡技术燃烧室有更好的流场形式,其在凹腔内形成的涡更靠近凹腔顶端、范围更大,更不易脱落,空气与燃料的掺混更加充分。旋转流线涡燃烧室的燃烧效率高于传统驻涡燃烧室,且火焰长度更短,但总压损失比传统驻涡燃烧室大2%左右,损失了一定的经济效益。     

空气分级比对同轴分级燃烧室性能参数的影响

为掌握同轴分级燃烧室性能参数随空气分级比(主燃级空气流量的比值)的变化规律,以某同轴分级燃烧室为研究对象,数值分析了空气分级比对燃烧室的燃烧效率、总压损失、出口温度分布、污染物排放和绝热壁面最高温度的影响。结果表明：空气分级比主要会改变角涡位置的燃烧温度和高温烟气的停留时间;随着空气分级比的升高,燃烧室总压损失、出口温度分布系数、NO_x排放、绝热壁面最高温度逐渐升高,但燃烧效率、CO污染物排放、径向温度分布系数对空气分级比不敏感;在同轴分级燃烧室设计中,在保证燃烧稳定的前提下可采用较小的空气分级比以实现燃烧室高效、低阻、低污染燃烧。     

初始条件对燃气轮机DLE燃烧室性能影响研究

以单头部中心分级旋流干式低排放(Dry Low Emission, DLE)燃烧室为研究对象,以天然气为燃料,针对不同的全局当量比、进口温度、进口压力条件开展试验测试和数值模拟,研究燃烧室的燃烧性能以及污染物排放的变化规律。研究发现：随全局当量比增大,中心回流区长度略有增大、宽度变窄、回流速度增大,燃料量的增加使得高温区面积明显扩大,燃烧室出口温升明显增大,出口温度分布系数变化不大,燃烧室出口CO和NO_x排放摩尔分数明显增大;随进口温度的增大,中心回流区长度先明显增大再减小、宽度变窄、回流速度先增大再减小,进口空气温度的升高使得反应速率加快从而导致燃烧室出口温度升高,但温升、出口温度分布系数变化不大,CO和NO_x排放摩尔分数增大;随进口压力的增大,中心回流区长度、宽度略有增大,回流速度增大,燃烧室内部和燃烧室出口温度无明显变化,出口温度分布系数减小,CO和NO_x排放摩尔分数受影响较小。     

微型燃气轮机燃油燃烧室燃烧特性的模化试验研究

基于模化试验方法,对设计的100kW级微型燃气轮机燃油燃烧室在额定工况下的性能以及在保持微型燃气轮机燃烧室出口排气温度不变的情况下,改变进口空气温度对燃烧室燃烧特性的影响进行了研究。结果表明,燃烧室燃烧效率达到99%以上,总压恢复系数达到94.5%,出口温度最大不均匀度低于20%,NOx排放指标低于9g/kg,火焰筒壁面温度分布均匀。此外,随着燃烧室进口温度的升高,燃烧效率增大,出口温度最大不均匀度减少,CO和UHC的排放指标明显降低,但总压恢复系数有所降低,NOx排放指标有所升高。     

火焰筒扩张角与旋流匹配对燃烧特性的影响

为研究旋流器流量分配对干式低排放(Dry Low Emission,DLE)燃烧室燃烧特性的影响规律,针对单头部中心分级旋流燃烧室,以天然气作为燃料,在保持旋流数不变的前提下开展两级旋流器不同空气分配比例下的试验测试和数值模拟,获得不同结构参数条件下燃烧室的综合燃烧性能以及污染物排放等变化规律。研究表明：随主燃级/预燃级旋流器流量比增大,燃烧室中心回流区变小、回流区长度变短;预燃级局部当量比的增大造成燃烧室出口CO排放增加,主燃区燃烧加剧,热力型NOx排放也增加;同时,燃烧室中心高温区域向燃烧室出口方向扩张,出口温度分布均匀性变差。     

辅助动力装置全环形燃烧室燃烧性能试验研究

针对某型辅助动力装置全环形燃烧室开展了整机燃烧性能试验研究。采用温度耙测量全环形燃烧室出口温度分布,研究不同进口温度和油气比条件下辅助动力装置燃烧室整机燃烧性能。试验结果表明:随着进口温度和油气比的增加,燃烧室出口温度相应增加,但温度分布规律基本保持不变,出口温度分布系数(OTDF)小于0.2,径向温度分布系数(RTDF)基本小于0.1,而燃烧效率和燃烧室进出口压力损失系数增加;随着进口总温的增加,燃烧室贫油熄火油气比逐渐减少(余气系数增加),但燃烧室的贫油熄火余气系数均大于13。     

国产重型燃气轮机单管燃烧室性能试验研究

以某国产重型燃气轮机单管燃烧室为研究对象,通过全压试验进行燃烧室出口温度场分布品质、火焰筒壁面温度、燃烧效率和压力脉动等性能参数的录取,将试验结果与中压模拟试验进行对比分析,验证燃气轮机燃烧室性能设计的合理性。试验表明,全压试验燃烧室出口温度场分布指标满足设计要求、出口温度场分布云图和火焰筒壁面温度与中压模拟试验具有相似趋势,中压模拟试验的火焰筒局部壁面温度高于全压试验结果,全压试验所测燃烧室燃烧效率高于中压模拟试验。研究获得的数据为燃气轮机在示范电站的整机运行考核提供参考,同时对国产其余型号燃气轮机燃烧室的全压试验具有一定的指导意义。     

湍流燃烧模型在燃气轮机燃烧室模拟中的运用与对比

利用Fluent商业软件,对燃气轮机燃烧室C16H29非预混燃烧流场进行数值模拟。针对燃烧室的额定工况,分别采用简单概率密度函数模型、涡耗散模型、涡耗散概念模型的2步反应和5步反应过程,对湍流燃烧流场进行对比数值分析,同时,考察燃烧室Thermal和Prompt NOx排放性能。通过比较发现,有吸热反应过程的EDC-5步模型所得流域内燃烧区温度较低;出口温度均匀性最好,最大不均匀度28%;NOx排放量最少。结果表明,该模型能够更合理地预测燃烧室的流场分布。     

某重型燃气轮机燃烧室的性能试验与调试

在中国一航涡轮院高压试验台上,对中国第一台具有自主知识产权的某重型燃气轮机(E级)燃烧室进行了燃用天然气的性能试验与调试,着重于燃烧室出口温度场试验与调试以及污染物排放含量试验.结果表明:设计工况下燃烧室出口周向温度分布系数为0.30,径向温度分布系数为0.13,排放污染物含量(NOx)为 204 mg/m3,这些指标均超出设计要求.通过调整火焰筒掺混孔尺寸,增加预混燃烧比例,使周向温度分布系数降为0.20,达到设计要求,并使径向温度分布系数降为0.10,接近设计要求.此外,还从理论上分析了燃烧室排放超标的原因及改进方向.     

不同进口条件对微小尺度驻涡燃烧室性能的影响

为研究进气参数对含导流片及钝体的微小尺驻涡燃烧室性能的影响,对不同进口温度、进口速度以及当量比等参数影响下的燃烧流动进行了研究。结果表明:进气参数的变化对钝体回流区范围均有影响,当量比的增大使回流区范围减小,速度和温度的增大使回流区范围增大,但温度的影响较为明显。当量比对燃烧效率的影响较大,Φ≤1.0时,燃烧效率较高,Φ1.0时,燃烧效率迅速降低。进气速度对总压损失的影响较大,当v=50 m/s时,总压损失达到11.38%。     

天然气塔式同轴分级燃烧室掺氢燃烧特性 数值模拟研究

为了解天然气掺氢对贫预混燃气轮机性能的影响,采用Chemkm-pro研究了燃料的化学反应动力学 特性,对比了不同当量比、掺氢比下的绝热火焰温度、层流火焰传播速度及点火延迟时间,结果表明掺氢能缩 短燃料点火延迟时间,增加绝热火焰温度及提高火焰传播速度。进一步以天然气塔式同轴分级燃烧室为研 究对象,研究了掺氢比对燃烧室燃烧场分布及燃烧效率、总压损失系数、温度分布不均匀度、一氧化碳及氮氧 化物排放量等性能参数的影响。结果表明,随着掺氢比的增加,燃烧效率上升,总压损失系数增加,温度分布 不均匀度下降,一氧化碳排放量下降,氮氧化物排放量增加。掺氢比在35%时燃烧室发生回火。在30% ~ 35%掺氢比范围内,燃烧室性能参数变化较大。其中,总压损失系数增幅为24. 74%,温度分布不均匀度降幅 为31.11%,氮氧化物排放量增幅为416.12%。     

Experimental Investigations on NOx Emission and Combustion Dynamics in an Axial Fuel Staging Combustor

Axial Fuel Staging(AFS)technology is an advanced low-emission combustion method in modem gas turbine,which divides the combustor into two axially arranged combustion zones.For revealing the characteristics of axial staged combustion,an industrial-grade combustor was designed and built.The distribution of temperature and velocity field in the combustor was presented with numerical simulation.And an Atmospheric Combustor Test Rig for axial staged combustion was built.The flow resistance characteristics of the combustor were measured at first.Then the effects of the equivalent ratio and the preheating temperature on the pollutant emission and combustion instability were investigated.The results show that the total pressure recovery coefficient in cold state is always above 98%;starting the secondary combustion at low load can reduce NO emissions by 50%,and can suppress the combustion oscillation amplitude of the combustor.At the design point with φ=0.62 and preheating temperature=400°C,NO emission and CO emission are 15.68 and 4.22 mg/m³(@15%O₂).     

当量比对涡轮叶间燃烧性能影响的数值模拟

为探究涡轮叶间燃烧性能,设计了4种不同当量比的工况,利用 FLUENT 软件的 Realizable k-ε湍流模型、PDF 燃烧模型、DO 辐射模型和离散相模型对燃烧室的流动及燃烧进行数值模拟.结果表明:燃烧室能在广泛的当量比(2.59~0.81)下保持性能稳定,燃烧效率保持在96%以上、总压损失低于2.4%,气体温度提高650,K 左右;降低当量比,能够提高燃烧效率,降低 CO、UHC、NOx 等污染物排放,改善温度分布,但会造成更大的总压损失;最优当量比等于1.00,此时燃烧效率在99.95%以上,总压损失相对低(1.5%),出口径向温度呈抛物线型分布,最适合燃烧室设计.与文献对比发现,选取的工况合理,其结果对涡轮叶间燃烧室设计具有参考价值     

Numerical comparison of premixed H2/air combustion characteristic of three types of micro cavity-combustors with guide vanes,bluff body,guide vanes and bluff body respectively

Micro-scale combustion is facing the problems of ignition difficulty, combustion instability, and low combustion efficiency. Therefore, it is necessary to improve the combustion characteristics in micro-combustor to expand the application range of micro-combustor. Focusing on the problem of the weak preheating effect of the micro cavity-combustor, the guide vanes are constructed to enhance the combustion near the cavity, and further combine with the bluff body to enhance combustion. The combustion characteristics of three types of cavity combustors with guide vanes (CCGV), bluff body (CCBB), bluff body, and guide vanes (CCGB) respectively are compared and analyzed under different inlet velocities (8–32 m/s), equivalence ratios (0.6–1.4), and wall materials (quartz glass, steel, and SiC). Results show that the guide vanes can greatly improve the combustion intensity near the cavity and improve the combustion stability of the cavity combustor. The combustion efficiency of CCGV and CCGB are increased by 43.04% and 85.96% respectively than CCBB when the inlet velocity is 32 m/s. The reaction heat of CCGV is 244.5 W when inlet velocity is 32 m/s, which is 0.55 times and 1.57 times that of CCGV and CCBB, respectively. The temperature uniformity and mean temperature of the outer wall of CCGV and CCGB both are better than that of CCGB. The combustion efficiency of CCGB is the highest among three combustors under the same equivalence ratio, especially when the equivalence ratio is less than 1. The reaction intensity in the cavity of the CCGV and CCGB with steel wall material is highest than that of the combustor with the other two wall materials. Wall materials with high thermal conductivity have a better preheating effect. Compared with quartz as the wall material, the mean temperature of the external wall of CCGV and CCGB using steel and silicon carbide as the wall material both increase by more than 130 K, and the wall heat loss both increase by more than 50%.     

基于气液两相的导叶对液力透平内部流动规律的影响

为了研究气液两相条件下导叶对液力透平内部流动特性的影响,现选取比转速为55.7的离心泵反转作为液力透平,并在液力透平叶轮进口添加一组负曲率导叶,设计出含导叶的水力模型,研究含气工况下导叶对液力透平性能的影响。研究发现:添加导叶前蜗壳和叶轮流道内压力分布和气相分布不均匀,且含气率越高均匀性越差,过流部件内流动较为紊乱,蜗壳和叶轮流道内出现了旋涡;添加导叶后,在较高含气率工况下叶轮流道内压力分布相对均匀且混合介质的流动情况得到改善,水力损失减少;添加导叶后透平最优效率点的值要高于未添加导叶的最优效率点的值,但随着含气率的提高,添加导叶的液力透平效率比未添加导叶的透平效率下降快。     

重型燃气轮机燃烧室设计与试验研究

完成了用于110MW级重型燃气轮机的干低排放燃烧室的设计和第一阶段试验验证。燃烧室采用轴向分级的贫油预混燃烧技术降低NOx排放,将火焰筒头部分为环形区、预混区和扩散区三个燃烧区。单管燃烧室全尺寸中压试验结果表明：在第一种工作模式下,燃烧室的总压损失、起动点火、燃烧效率、出口温度分布、压力脉动和火焰简壁温均满足设计要求,但NOx排放超过设计要求。受周期和试验条件限制,第二种工作模式下的NOx排放试验尚未完成。     

Control of Collection Efficiency for Axial Flow Cyclone Dust Collectors with Fixed Guide Vanes and with Funnel Shaped Exit Pipes

The experimental result of the collection efficiency of the axial flow cyclone with the fixed guide vanes is lowerthan that with the tangential inlet pipe to the cyclone body due to the weak angular momentum transfer given byflowing through the guide vanes.However,one of the interesting points is the control of the collection efficiencydepended on the funnel shaped exit pipes.The collection efficiencies for these funnel shaped exit pipes aredepended on the Froude number.Then,in this paper,the experimental results of the pressure drop and also thecollection efficiency using the fly-ash particles and also the comparison of the calculated results of the collectionefficiency with the experimental results are described in detail.     

超音速燃烧的喷嘴模型研究

在综合现有的强化混合技术基础上，提出了一种新的喷嘴模型－低角度分级喷嘴模型，并设计了缩尺寸燃烧室。通过燃烧室入口马赫数为２的氢燃烧超音速燃烧实验，获得了超音速燃烧室中壁压沿轴向的变化规律，证明了低角度分级喷嘴模型燃烧室比目前公认的后掠斜坡喷嘴模型燃烧室有更高的燃烧效率。     

Computed effect of guide vane shape on performance of impulse turbine for wave energy conversion

This paper deals with the computational fluid dynamics (CFD) analysis on effect of guide vane shape on performance of impulse turbine for wave energy conversion. Initially, experiments have been conducted on the impulse turbine to validate the present CFD method and to analyse the aerodynamics in rotor and guide vanes, which demonstrates the necessity to improve the guide vanes shape. The results showed that the downstream guide vanes make considerable total pressure drop leads low performance of the turbine and hence three‐dimensional (3‐D) inlet and downstream guide vanes have been designed based on well‐known vortex theory to improve the efficiency of the turbine. In order to prove the improvement in efficiency due to 3‐D guide vanes, CFD analysis has been made on impulse turbine with 2‐D and 3‐D guide vanes for various flow coefficients. As a result, it is seen that the present CFD model can predict the experimental values with reasonable accuracy. Also, it is showed from the numerical results that the efficiency of the turbine can be improved by average of 4.5 percentage points by incorporating 3‐D guide vanes instead of 2‐D guide vanes. The physical reason for improvement in efficiency of the turbine due to 3‐D guide vanes has been explained with the CFD flow insight pictures. As the turbine operates in fluctuating flow conditions, the performance of the turbine with 2‐D and 3‐D guide vanes have been calculated numerically using quasi‐steady analysis. Furthermore, the performance of the turbine has been predicted for one year based on Irish wave climate to show the feasibility of using 3‐D guide vanes in actual sea wave conditions. Copyright © 2005 John Wiley & Sons, Ltd.