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Swirl type combustor for study of spray combustion has been designed. Using this combustor luminous flame and non-luminos flame can be produced by shifting the spray nozzle position without changing the operating conditions. From the experimental studies the following results were obtained. (l) Supplying combustion air from tangential port, swirl number of S=0.99 was obtained. The circulation length was nearly equal to the combustion tube diameter. (2) Flame appearances were controlled by diffusion process of fuel spray and combustion air. If fuel spray was injected into a reverse flow in torroidal vortex, combustion process was so fast that non-luminous flame was obtained. (3) Paying attention to the primary combustion, combustion efficiency of swirl-type combustion was found better in the case of luminous flame, and it was shown combustion performances were controlled by the flow pattern and the spray directions.

The pressure dependences of carbon particle cloud radiation and of nunluminous gas radiation are examined individually in order to predictradiation from luminous flame of liquid fuel at high pressures. For carbon particle cloud radiation, the equation of carbon formation is determined in terms of pressure and excess air factor with reference to the experiments on the soot formation from vaporized fuel at low excess air factor and on the combustion of a single droplet of fuel in a large chamber. For nonluminous gas radiation, the expressions obtained by Edwards are adopted. A method is developed to calculate the luminous flame radiation at high pressures using the above expressions and the experimental results at an atmospheric pressure. The calculated results agree well with the measured values. The maximum, average and endzone absorption coefficients in the luminous flame can be easily calculated.

The temperature measured in the 1st Report is the one which is averaged through an optical path in the luminous flame zone. In the first step of this paper, the physical meaning of this average temperature is discussed. For this purpose, the flame is divided into many layers and the radiation from the whole flame is considered as the result composed of radiation and absorption of each layer. In the second step, based upon the above consideration, the temperature distribution in a flame is measured. To divide the flame into many layers, and to measure the radiation effect of each layer, a light-intercepter is inserted into the flame and displaced successively across the flame. By this technique, a change of the flame temperature distribution versus crank angle is measured on a CFR engine. As one of the results, Hopkinson's effect is ascertained. Namely, at the instant when the flame spreads over the combustion chamber, it is found that the temperature of gas around the park plug is about 300°C higher than that of gas near the cylinder wall.

One method to measure the instantaneous flame temperature within the cylinder of a gasoline engine by means of the absolute radiation method is proposed. The radiation energy of D-line emitted from a trace of sodium, which is added to fuel, is measured by an optical-electronic system. Then, the measured energy is converted into the equivalent black body temperature. This temperature may be considered as the flame temperature which is averaged through an optical path in the luminous flame zone. In the process of conversion, the half-width of D-line is determined experimentally and the number of Na atoms radiating in the optical path is evaluated theoretically. As the optical system, a quartz window, 4 limiting diaphragms, an interference filter and a fiber-scope are arranged in order. And a light beam having 1 mm in diameter is introduced to a photo-multiplier by means of the fiberscope. By this technique, the flame temperature in CFR engine is measured under various operating conditions.

From such a standpoint that a radiation from a luminous flame is due to the small solid particles (so-called"soot"), a fundamental research for the radiation from the luminous flames of the propane-air and city gas-air was carried out on the basis of Mie theory concerning radiation. The purpose of this paper is to measure the scattered parts and attenuated parts of incident lights about a flame and study the radiation of a luminous flame systematically. A mean diameter D32 of soot particles, defined as [numerical formula], where N (D) dD is the probability that the soot diameter is in the range of D and D+dD, is suggested to discuss the relation between the scattered light from the flame and the attenuated light by the luminous flame. It is showed that the values of D32 obtained by scattering and attenuation are 1 400A regardless of diffusion or premixed flame. The density of the soot particles, Cv, is experimentally obtained from the attenuation of the incident light in our research, and general consideration of radiation from luminous flames is given.

In this paper, the radiant heat transfer from a luminous flame is treated theoretically and experimentally, from the view point that the radiation from a cloud of carbon particles is most effective. In the case where only the cloud of luminous carbon particles under uniform temperature and uniform volume fraction is concerned with radiation, the relation between the total emissivity and X has been found, where X is the function of volume fraction, thickness and temperature of flame. And the calculated value agrees well with the Schack's results. Next, in the luminous flame, the relation between the total emissivity and X, has been found. Moreover, experimentally the relation between the emissivity of a luminous flame and X in the luminous flame which was formed artificially by inserting the carbon particles in a nonluminous flame, has been made clear by means of an optical pyrometer and a radiation pyrometer. The result of studies showed that the experimental values agreed with the above mentioned theoretical analysis.