International Journal of Applied Engineering Research
  • Year: 2009
  • Volume: 4
  • Issue: 4

Optimization of Fin Geometry of An Exhaust Heat Exchanger For Automotive Thermoelectric Generators

  • Author:
  • Khalid M. Saqr, Mohd N. Musa
  • Total Page Count: 16
  • Page Number: 481 to 496

Department of Thermofluids, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Skudai, 81310 - Johor Darul'Takzim

NomenclatureDh

Hydraulic diameter (m)

DO

Outer diameter (m)

Dmd

Meltdown diameter (m)

NuDB

Dittus-Boelter Nusselt

Di

Inner diameter (m)

Dr

Root diameter (m)

Hf

Fin height (m)

β

Helix angle

Re

Reynolds Number

Amd

Meltdown area (m2)

Tf

Fin thickness (m)

S

Offset distance (m)

LP

Pipe length (m)

P

Pressure (Pa)

f

Friction factor

Pr

Prandtl number

N

Number of fins

k

Thermal conductivity of fluid (W/m2.K)

Ph

Helix pitch (m)

w

Discontinuity distance (m)

ρ

Density (kg/m3)

Mass flow rate (kg/s)

Abstract

Thermoelectric generators (TEGs) are the most eminent systems potentially identified to supply the increasing demand of electric power in contemporary passenger vehicles. These generators recover the iste heat of exhaust or/and engine coolant into electricity via Seebeck thermoelectric effect. One of the most important challenges in developing efficient TEGs is the design and optimization of the heat exchanger(s). We describe a computational methodology developed to optimize internally-finned tubular exhaust heat exchangers for this purpose. The optimization process is demonstrated through studying a novel heat exchanger concept. The pressure drop, Nusselt Number, and convection heat transfer coefficient were calculated for a geometry matrix representing fin length varying from 0.001 m to 0.02 m, and fin number of 5 to 35 fins. Three different exhaust flow rate, corresponding to engine cruise condition, were used in the analysis. The optimization algorithm and code are explained in details.

Keywords

Internal fins, Heat exchanger, TEG, Exhaust heat, Optimization