Numerical Simulation And Experimental Investigation On Self-excited Oscillating-jet Burner

A set of self-excited oscillating-jet burner and its combustion experimental system was designed for efficient combustion and low pollutant emission of fuel gas, according to the "coal to fuel gas" policy promoted in many domestic cities as well as the widely usage of natural gas as high quality, high efficiency and clean energy in various industries. This research includes the numerical simulation of velocity field and temperature field in The combustion chamber and NO content in combustion products as well as relevant experimental work.First of all, according to relevant bibliographies at home and abroad, five kinds of self-excited oscillating-jet burners were designed based on previous researches. The key technique of the burners is the structural characteristic of the sudden expansion chamber of noncircular inlet, In addition, four kinds of free-jet burners were designed in order to compare with self-excited oscillating-jet burners. The whole experimental system was confirmed after optimization and the experimental system was set up according to it.Secondly, the simulations of self-excited oscillating-jet burner and free-jet burner were done. The basic control equation was analyzed and proper mathematical model was chose. The geometrical and physical model was installed based on the standard size of self-excited oscillating-jet burners of sudden expansion chamber of noncircular inlet. Then, the grid partition method was built. The boundary conditions of numeral model were described according to the thermal load and environmental parameters. And the residual was set according to the convergence criteria, and the result was produced. Since the reference plane is taken from non axi-symmetric xy and xz, the velocity field, temperature field and concentration field of NO were described. The results from numerical simulation verified the realization of high efficiency and low pollutant of natural gas combustion in self-excited oscillating-jet burner.Finally, the experimental research works were done. The shape and volume of flame, the effect on flame of each burner were studied in ignition experiment in free space. According to the measurement of each measured point in combustion chamber, the temperature distribution was deduced and the components of the combustion product were studied. In all, it comes to the conclusion that the key factor for the realization of energy saving dues to the existence of self-excited oscillating.This thesis lays a theoretical foundation for choosing proper self-excited oscillating-jet burners based on the structural characteristic of fuel gas industrial boilers and furnaces.