بررسي تجربي عملكرد يك نمونه مشعل متخلخل و تحقيق در مورد امكان استفاده از آن در محفظه احتراق توربين هاي گاز

چكيده انگليسي :

99Experimental Study of the Performance of a Porous Burner and Possibility of using Porous Burner in a Horizontal Combustor Mohamad sadegh zekavatmand ms zekavatmand@gmail com Date of Submission 20 September 2013 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Email address mohsen@cc iut ac irM Davazdahemami Assoc Prof Abstract The use of porous media in the combustion chamber is a very efficient method to reducepollution and energy consumption These burners have advantages over free flame burners becauseof less production of NOx preheating the mixture of fuel and air before firing and smaller size ofthe burner at the same firing rate In porous burners all three mechanisms of heat transfer namelyconduction Convection and radiation are present whereas in the free flame burners theconvection mechanism is the major factor for heat transfer Open Range triggering uniformdistribution of heat in the combustion chamber faster warm up and significant reduction of noiseare other advantages of this type of burners that favor the use these burners frequently in variousapplications The present study experimentally investigates properties of porous media and theirperformance as burners with different firing rate as compared to an existing free flame burner Amixture of air and natural gas is used as the feed fuel The porous burner was designed such thatthe combustion mixture enters into a cylindrical porous medium along the axial direction and exitsin radial direction The location of flame at radial direction is monitored by using thermocouplesfitted in several radial locations There are generally four types of flames in porous media burners Only two types submerged combustion and surface combustion of these are observed are studiedin this research The measuring station for species concentration is at the exit of the combustionchamber After stabilizing each flame to achieve a steady state condition the effects ofequivalence ratio and firing rate on the performance of porous and free burners were examined Inthis study three sets of experiments were performed First the performance of the porous burnerand its exhaust gas analysis performed while the exhaust damper was fully opened Next the effectof back pressure on porous burner performance and pollution was studied by adjusting the exhaustdamper Finally the performance of a free flame burner and its pollution was investigated Resultsshow that in a porous medium having 26 2 mm length surface combustion and submergedcombustion take place The porous burner operating at equivalence ratio of 0 9 submergedcombustion has performed better than when operating at the equivalence ratio of 0 8 surfacecombustion Increased firing rate in porous medium burner led to increased concentrations of NOand CO2 and reduced volume fractions of CO and O2 Closing the exhaust damper has nosignificant effect on the amount of O2 and CO2 and causes a small decrease in the concentrationof CO and a small increase in NO concentrations The characteristics and performance of aconventional free flame burner were also determined and compared with the porous burner Results show that increasing equivalence ratio in conventional burner increases the concentrationof CO NO and reduces the concentration of O2 in combustion products Also increasing firing ratecause an increase in concentration of NO and a decrease in CO However it does not have asignificant effect on the concentration of O2 and CO2 Keywords porous Burner Air pollutants equivalence ratio porous Burner fireing rate

ذكاوتمند، محمدصادق

بررسي تجربي عملكرد يك نمونه مشعل متخلخل و تحقيق در مورد امكان استفاده از آن در محفظه احتراق توربين هاي گاز

مشعل محيط متخلخل , نرخ آتش , نسبت هم ارزي , آلاينده , مشعل شعله آزاد