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A study for the ignition of flammable premixture that contains CH4 and H2 at stagnation point of a hot rod was conducted, and a comparison between calculated and experimental results was reported in the paper. The catalytic reforming reaction of CH4 with steam in the furnace produced a small amount of H2, which was premixed with air. The mixture was then ignited by a hot rod located inside the test vessel. Experimental and calculated results both show that a small quantity of H2 can greatly reduce the ignition temperature, explained by the high reactivity and high diffusivity of H2. A new method for calculating the equivalent overall reaction rate is described in the paper, in which the gradient of local Damkohler number instead of the traditional temperature gradient on the surface of the hot rod is adopted as an ignition criterion. [Copyright &y& Elsevier]

Using a microwave plasma generator, compressed air microwave plasma was excited under 1 - 5 atm pressures. Under different pressures and different incident microwave power, the emission spectra of compressed air microwave plasma were studied with a spectra measuring system. The results show that continuum is significant at atmospheric pressure and the characteristic will be weakened as the pressure increases. The band spectra intensity will be reduced with the falling of the incident microwave power and the band spectra were still significant. The experimental results are valuable to studying the characteristics of compressed air microwave plasma and the generating conditions of NO active groups.

A set of spectrum diagnostic system was established. With this system, spectrum analysis was carried out for the plume signal of enhanced arcjet thrust using catalytic decomposition products of hydrazine as propellant. Excitation plume temperatures for various wavelengths were obtained through measuring spectral radiation intensity. The averaged excitation temperatures were analyzed based on Boltzman diagram. The results show that there is the highest temperature in the axial center of plume and the temperature drops quickly in the radial direction. The intensity of thermodynamic non-equilibrium weakens with a decrease in current and an increase in radial distance. The temperature of the plume rises with an increase in the proportion of ammonia in the catalytic decomposition mixture of hydrazine.

The difference between electron temperature and excitation temperature is analyzed in the aspect of statistics thermodynamics. It is presented clearly that the temperature acquired by spectral line intensity method is not free electron temperature, but internal electronic excitation temperature of heavy particle. Under thermal equilibrium condition, the excitation temperature is equal to the electron temperature, while under non-thermal equilibrium condition, the excitation temperature is not equal to the electron temperature. In the study of arc jet plume in vacuum chamber, spectral line intensity method was employed to measure the apparent excitation temperature of arc jet plume, and Langmuir probe was employed to measure the electron temperature of arcjet plume. The big difference between the excitation temperature and the electron temperature proved that the temperature acquired by spectral line intensity method is not free electron temperature.