Design And Experimental Study Of A Full Blown Partial Premixed Burner For Gas Water Heater

At present,most of the burner of gas water heater on the market is low pressure ejector type part premixed burner,which mainly rely on the use of gas ejector structure of self-pressure ejector nozzle of the air around an air.The ejector has a certain self-adjustment ability,when the combustion load changes,the amount of air injected is also changed,so as to ensure the relative stability of the primary air coefficient.But because of the ejecting ability by the fire hole area,hole depth,fire nozzle and nozzle position,gas properties,atmospheric environment,life and other factors,have a great change in a moment of air ejector,which can’t guarantee the best combustion condition,resulting in higher emission of pollutant concentration.In view of this,the study of the full blown partial premixed burner has become an important research direction.In this paper,the thermal characteristic experiment is depend on the ull blown partial premixed burner which is self-designed,built the experimental platform to study the influence of thermal load,one or two air coefficient and excess air coefficient on the combustion performance of the burner by controlling the one or two air flow through the air pipe on the experimental system of valve regulated drum into the burner to change the one or two primary air coefficient and excess air coefficient,and then provide a theoretical basis for the full blast of part premixed burner development.The study found that in the rated gas pressure 2000 Pa and the 92%-104% range of heat load in the design of the heat load of the burner,the air coefficient is reasonable when combustion were able to reach the good effect,did not appear yellow flame,fire off,tempering and other bad combustion phenomena.The experiment show:(1)The primary air coefficient has a great influence on the flame height and stability.When the primary air coefficient is low,the burner flame is cloudy,blue light and long;with the increase of the primary air coefficient,the flame shortened,more clear and pale blue flame deepened;the primary air coefficient increases to a certain value,the flame began to wave,and even to shrink with the fire orifice flush,the combustion becomes unstable.When the primary air coefficient is determined,the two air coefficient and excess air coefficient has little influence on the flame’s height and shape,with the increase of two air coefficient and excess air coefficient,the light blue flame deepened.(2)The input heat load,primary air coefficient,two air coefficient and excess air changed coefficient have an great influence on the combustion products and chamber temperature.In the conditions of stable combustion,when the air coefficient is certain,,the greater of the heat load,the higher concentration of the CO,NOx and the chamber temperature;when the thermal load and the primary air coefficient is certain,with the increase of two air coefficient,the excess air coefficient increased,the concentration of the CO,NOx decreased,the temperature of the combustion is reduced;when the heat load and excess air coefficient is certain,the higher of the primary air coefficient,the lower concentration of CO and NO,but the temperature of the combustion chamber with little change.Under various conditions,when the excess air coefficient reaches 1.86,the CO emission concentration can satisfy the requirement that the CO concentration in the flue gas should not exceed 1000 ppm when the excess air coefficient is 1.When the input heat load for the design of the heat load of 98%,the primary air coefficient is 0.44,the two air coefficient is 1.48,the excess air coefficient is 1.92,emissions of burner combustion products in CO,NO,NO2 and NOx were significantly lower than that of other conditions.