ガスタービンにおける燃焼に関する計測法

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In this paper, the measuring methods of the characteristics of liquid fuel spray, gas flow in combustor and combustor performance are described. Spray characteristics such as droplet size and weight flow distribution has a significant effect on combustor performance. Many interesting techniques have been developed for the measurement of droplet size, and they may be grouped into two methods. The first is the sampling method, in which the droplet size distribution is calculated from many spray samples by taking account of weight flow distribution, and for spray sampling, immersion, impression, direct catching and direct photographying methods are commonly used. The second is the one, in which the droplet size distribution is obtained directly either by counting and sizing a representative sample of the whole spray or by classifying the whole spray by size with the aid of sieves (applicable only for frozen droplets), cascade-impactor and so on. Weight flow distribution can be measured with single collection probe for any configuration of spray, but for measuring diametral and circumferential distributions in conical-shaped sprays, it is convenient to use a collection rake and a sectored patternator, respectively. Simultaneous measurement of both droplet size and weight flow distributions is mostly desired, and the method developed by the author is such a technique. In this method, a set of samples are caught on a long belt simultaneously, the exposure time of all samples to spray being held constant, and therefore, the information on weight flow distribution can be obtained by calculating the volume of droplets appeared in unit area of each sample. Another feature of this method is its applicability under any condition of ambient gas. In most continuous combustion systems of practical use, the aerodynamic factors are important in respect to flame stabilization, rapid mixture formation and so on. The study of gas flow under burning condition will provide the most useful information, but usually is very expensive of time, money and material, and furthermore, in such a test difficulties arise relating to the temperature measurement of hot gases when the velocity distribution is to be measured. These defects led to the development of isothermal modeling techniques, in which cold air or water is used as the fluid, and the gas flow is either visualized with the aid of streamers and tracers or measured by various instruments. Isothermal modeling, in spite of lacking in simulating the density change due to combustion, serves as a useful tool for satisfactory operation of combustor, and some examples are shown to illustrate the good qualitative correlation between flow patterns at isothermal conditions and those obtained under burning conditions. There are many requirements to be satisfied by the combustor, and the main items in respect of measurements may be combustion efficiency, pressure loss, outlet gas temperature distribution and flame tube temperature. The measuring methods of these items are described together with several applications of gas analysis to the combustor development. The examples of the latter are the measurement of combustion efficiency, the calculation of temperature of very hot gases whose temperatures are so high that the use of ordinary thermocouples is not adequate, and the prediction of outlet gas temperature distribution from isothermal test. The main part of this paper was originally presented by the author at the 210th Lecture Meeting of J.S.M.E. (Measurement on Combustion) which was held on April 20 and 21, 1964.
独立行政法人海上技術安全研究所の論文
1965-03-31

著者

根矢清
運輸省船舶技術研究所機関開発部

ガスタービンにおける燃焼に関する計測法

スポンサーリンク

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