The book deals with the numerical simulation of compact heat exchangers that are primarily used in dissipating heat generated by electronic components and assemblies. The forced-convective cooling of a horizontally based pin-fin assembly has been investigated for the pressure drop and heat transfer characteristics. The effect of pin fin’s thermal conductivity on the performance of heat exchanger is investigated by considering different fin materials. Subsequently the computations for different fin spacing along the stream-wise direction were carried out. The thermal and fluid-dynamic characteristics along the computational domain are discussed in detail. Finally the performance characteristics of triangular fin heat exchangers are studied and a comparison was made with circular pin fins. The results showed that circular pin fins perform better than triangular pin fins with less pressure drop. The book should be especially useful for the engineers and researchers working in the field of conjugate heat transfer and compact heat exchangers.