Conjugate Heat Transfer Analysis of a Diamond Finned Double Pipe Heat Exchanger

An analysis of a conjugate heat transfer is numerically investigated in a diamond finned annulus of a double pipe heat exchanger using finite element method. The average Nusselt Number ([[EQUATION]]) is considered to investigate the thermal performance against different parameters. Present results dictate that for the fixed value of conductivity ratio [[EQUATION]]the smaller diamond fin height ([[EQUATION]]) with any number of diamonds fins [[EQUATION]] , give maximum values of ([[EQUATION]])  while for [[EQUATION]] , diamond fins having a height of 40%, for [[EQUATION]], diamond fins with 80%, and for [[EQUATION]], diamond fins with100% fin height give maximum value of heat coefficient for half fin-thickness ( [[EQUATION]] is [[EQUATION]]. For the case of [[EQUATION]], diamond fins having a height of 20% when the number of diamond fins varies from 4 to 8 with thickness [[EQUATION]] , diamond fins having a height of 80% when the number of diamond fins is 12 with thickness [[EQUATION]] and diamond fin having a height of 100% for[[EQUATION]] with thickness [[EQUATION]] , give maximum value of [[EQUATION]] . The optimal values of j-factor for [[EQUATION]] and [[EQUATION]] exist at [[EQUATION]] & [[EQUATION]] , [[EQUATION]] & [[EQUATION]] and [[EQUATION]] & [[EQUATION]], respectively.