EFFECT OF NOZZLE DIAMETER ON JET IMPINGEMENT COOLING SYSTEMDULFHARAH NIZAM BIN MEMTH ALIA report submitted in partial fulfilment of the requirements For the award of the degree of Bachelor of Mechanical Engineering PureFaculty of Mechanical EngineeringUNIVERSITI MALAYSIA PAHANGNOVEMBER 2009iiSUPERVISORS DECLARATIONIherebydeclarethatI havecheckedthisprojectandinmy opinionthisprojectis adequate intermsofscopeandqualityfortheawardofthedegreeofBachelorof Mechanical Engineering.Signature Name of Supervisor: WAN AZMI BIN WAN HAMZAHPosition: LECTURERDate:iiiSTUDENTS DECLARATIONIherebydeclarethattheworkinthisthesisismyownexceptforquotationsand summaries which have been duly acknowledged. The project has not been accepted for any degree and is not concurrently submitted for award of other degree.SignatureName: DULFHARAH NIZAM BIN MEMTH ALIID Number: MA06046Date:ivI humbly dedicate this thesis tomy lovely mom and dad, Rogayah Mahmud and Memth Alimy dearest sister, Shakina Shanaz, Nurul Anizah and Balqis Faradillamy dearest brother, Hariz Irfanmy heart and soul, Nurul Farahdilahwho always trust me, love me and had been a great source of support and motivation.vACKNOWLEDGEMENTSFirstIwouldliketoexpressmygratefultoALLAHs.w.t.asfortheblessing given that I can finish my project.Inpreparingthispaper,Ihaveengagedwithmanypeopleinhelpingme completingthisproject.First,Iwishtoexpressmysincereappreciationtomymain thesissupervisorMr.WanAzmiWanHamzah,forencouragement,guidance,advices andmotivation.Withouthiscontinuedsupportandinterest,thisthesiswouldnothave been the same as presented here. The next category people who help me to grow further and influence my project are my colleagues especially my projectmate Mr.Mohammad Khyru Bin Aris and Mr. Khaider Bin Abu Bakar who always help me in order to finish this project. I would like toexpressmygratitudeespeciallytoallFKMlaboratoryinstructorsfortheir helpand advices. I appreciate very much to them because of the idea and information given.Iacknowledgemysincereindebtednessandgratitudetomyfamily fortheir love, dream and sacrifice throughout my life. My father, mother, brother and sisters that alwayssupport,motivationandencouragemetosuccess.Icannotfindtheappropriate words that could properly describe my appreciation for their devotion, support and faith inmyabilitytoattainmygoals.Specialthanks shouldbegiventomypresentations panel members.Iwouldliketoacknowledgetheircommentsandsuggestions,which was crucial for the successful completion of this study.Thank you all.viABSTRACTThisresearchfocusedonthestudyabouttheeffectofnozzlediameteronjet impingementcoolingsystem.Theimpingingjetcanbedescribedasaphenomenon in whichthefluidexitingfromanozzleororificehitsawall orsolidsurfaceusuallyat normal angle. Impinging air jets have been widely used in many industrial applications inordertoachieveenhancedcoefficientsforconvectiveheating,coolingordrying.A singleairjet orarraysofairjets,impingingnormallyonasurfaceare aneffective method to enhance heat and mass transfer. Engineering applications that widely use air jets include cooling of hot steel plates, tempering of glass plates, drying of textiles and paper,coolingofturbineblades,electroniccomponentsandde-icingofaircraft.Experimentswereconductedtodeterminetheeffect ofnozzlediameteronthe heat transfercoefficientsfromasmallheatsourcetoajetimpingementcoolingsystem, submergedandconfinedair.Theexperimentwerecarriedoutwitha singlejetwith threedifferentnozzle diameter,d; 0.5,1.0,2.0 cmandfour dimensionlessjettoheat sourcespacing,S/d (6,8,10,12)weretestedwithinthelaminarjetReynoldsnumber ranging from 500-2300. The results indicate that the heat transfer coefficient, h increase withtheincreasingnozzlediameterat thestagnationpointregioncorrespondingto 0