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

为了应对燃气轮机系统改进的挑战，名古屋大学先进能源转换研究中心成立于1992年4月，该中心启动了一项研发计划，迄今已取得突破性的燃气轮机技术，名为化学燃气轮机(CGT)，其基础是先进的富油燃烧技术和涡轮叶片转子的C/C复合材料。主要部件包括富燃料燃烧器、贫油燃烧器、两套燃气轮机、一台蒸汽轮机和热交换器。该系统的一个重要特点是使用了富燃料燃烧，这里称之为化学燃烧，因为它的优点是：(1)它产生低水平的NO_x，(2)富燃料燃烧室的废气在通过第一透平膨胀时产生动力，并且其H_2和CO组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气体…中产生更多的动力更多的涡轮，或可能在燃料电池中，(4)注意到目前在1773K以上无内冷的涡轮叶片运行的唯一候选材料是C/C复合材料，并且这种材料对高温氧化、燃料丰富的燃烧非常敏感，这导致废气中的氧量显著减少，非常适合这种应用。本文主要研究了以下几个方面的内容：(1)利用所研制的高压燃烧室进行高压富燃料燃烧；(2)利用所研制的微型化学燃气轮机进行烟气燃烧；(3)利用研制的微型化学燃气轮机，研究了甲烷-空气加压燃烧火焰结构对压力和当量比的依赖关系，为燃气轮机富燃料燃烧室的设计提供了详细的数据。在1 Mpa富燃料条件下，火焰具有典型的大气富燃料火焰的欠通风结构，而在1.5 Mpa以上的火焰具有贫油火焰的形状。与贫油条件下的火焰相比，富燃料条件下火焰长度对压力的依赖程度较小。在贫油条件下，火焰长度随压力增大而增大。(2)对高压燃烧进行了三维数值模拟。在贫油条件下，计算结果与实验结果吻合较好。化学动力学模型在富油条件下存在一些问题。(3)研制了实验室规模的化学燃气轮机，并对其特性进行了研究。微型燃气轮机燃烧室的长度为230 mm，内径为50 mm。在额定运行条件下，空气和甲烷的质量流量分别为62nL/s和22.8nL/s。在此条件下，当量比为3.0，压缩比为2.6，额定转速为10万转/分，额定输出功率为2.5kW。较少

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