Development of High Temperature Gas Turbine using Chemical Flame with New Idea.

为了应对燃气轮机系统改进方面的这些挑战，名古屋大学于1992年4月成立的先进能源转换研究中心启动了一项研发计划，迄今为止已经产生了一项突破性的燃气轮机技术，名为化学燃气轮机（CGT），该技术基于先进的富燃料燃烧和涡轮叶片转子的C/C复合材料的前景发展。主要部件包括一个富燃料燃烧器、一个低燃料燃烧器、两套燃气轮机、一个蒸汽轮机和热交换器。该系统的一个重要特点是使用富燃料燃烧，这里称为化学燃烧，因为它有以下优点：(1)它产生低水平的NO_x，(2)从富燃料燃烧室排出的废气在通过第一级涡轮机的膨胀过程中产生动力，并且在其H_2和CO成分中仍然含有化学能，(3)这种废气因此可以在第二级蒸汽或燃气中产生更多的动力。(4)注意到目前涡轮叶片在1773 K以上运行而没有内部冷却的唯一候选材料是C/C复合材料，并且这种材料对高温氧化和富燃料燃烧敏感，这导致排气流中的氧气量显着减少，非常适合这种应用。为了开发上述新系统，我们主要研究了以下几个主题：(1)利用开发的高压燃烧器在高压下进行富燃料燃烧；(2)利用开发的富燃料燃烧气体衍生的烟气燃烧；(3)利用开发的微化学燃气轮机进行基本性能特性的研究。我们获得了以下结果：(1)研究了甲烷-空气加压燃烧中火焰结构对压力和当量比的依赖关系，获得了详细的数据为燃气轮机设计富燃料燃烧室。在1 MPa富燃料条件下，火焰具有典型大气富燃料火焰的不通风结构，而在1.5 MPa以上的火焰具有贫燃料火焰的形状。富燃料条件下火焰长度对压力的依赖性比贫燃料条件下要小。在低燃料条件下，火焰长度随压力增大而增大。(2)对高压燃烧过程进行了三维模拟。在低燃料工况下，与实验和模拟结果吻合较好。由于化学动力学模型的存在，在富燃料条件下存在一些问题。我们开发了一个实验室规模的化学燃气轮机进行示范，并研究了它的特性。微化工燃气轮机燃烧室长度为230 mm，内径为50 mm。在额定工况下，空气和甲烷的质量流量分别设计为62 Nl/sec和22.8 Nl/sec。在此条件下，等效比为3.0，压缩比为2.6，额定转速为100,000 rpm，额定输出功率为2.5 kW。少

To respond to these challenges for gas-turbine system improvement, the Research Center for Advanced Energy Conversion, Nagoya University, established in April 1992, has launched an R&D program which has so far resulted in a break-through gas turbine technology, named the Chemical Gas Turbine (CGT), which has been based on promising developments in advanced fuel-rich combustion, and in C/C composites for the turbine blade rotor.The principal components are a fuel-rich combustor, a fuel-lean combustor, two sets of gas turbines, a steam turbine, and heat exchangers. An important feature of this system is the use of fuel-rich combustion, named here Chemical Combustion, because of its following advantages :(1) It produces low levels of NO_x,(2) the exhaust gas from the fuel-rich combustor produces power during its expansion through the first turbine, and still contains chemical energy in its H_2 and CO components, (3) this exhaust gas can thus produce more power in second stage steam or gas … More turbine, or possibly in a fuel cell,(4) noting that currently the only candidate materials for turbine blade operation above 1773 K without internal cooling are C/C composites, and that such materials are sensitive to high-temperature oxidation, fuel-rich combustion, which results in significantly reduced quantities of oxygen in the exhaust stream, is very well suited for this application.To develop the novel system proposed above, we mainly studied on the several theme as follows :(1) fuel-rich combustion under high pressure by using the developed highly pressurized combustor(2) flue gas combustion which derived from fuel-rich combustion gas(3) fundamental performance characteristics by using the developed micro-Chemical gas turbineWe have obtained the following result :(1) We investigated the dependency of the flame structure on presure and equivalence ratio in methane-air pressurized combustion to obtain detailed data for designing the fuel-rich combustor for the gas turbine. The flame under fuel-rich condition at 1 MPa had an underventilated structure like typical atmospheric fuel-rich flames, while the flame over 1.5 MPa had the shape of a fuel-lean flame. Under fuel-rich condition there was a smaller dependence of the flame length on pressure as compared with flames under fuel lean conditions. The flame length has increased with pressure under the fuel-lean conditions.(2) The three-dimensional simulation on highly pressurized combustion was performed. There are good agreement with experimental and simulated results under fuel-lean condition. Several problems for fuel-rich conditions exist because of chemical kinetic models.(3) We have developed a lab-scale chemical gas turbine for demonstration, and investigated its characteristics. The length of the combustor for the micro-chemical gas turbine was 230 mm and the inner diameter 50 mm. The mass flow rates of air and methane were designed as 62 Nl/sec and 22.8 Nl/sec at the rated operation, respectively. Under these conditions the equivalence ratio is 3.0, the compression ratio 2.6, the rated rotational velocity 100,000 rpm, and the rated output 2.5 kW. Less