Abstract: Heat exchanger is mainly associated with transfer heat from one fluid to another fluid either in direct contact with each other or separated by wall. The heat exchangers characteristics are concerned with the rate of heat transfer between the fluids with assuming the flow to be uniform throughout the core of the exchanger. But in actual practice it is usually the flow Non-uniformity that occurs and adversely affects the Heat Transfer rate and heat exchange properties of the heat exchanger. The major non-uniform flow is caused due to poor header design or restrictions in flow at microscopic level as a result of manufacturing operations on the surface. The CFD analysis of Heat exchanger is achieved considering the concept of Viscosity induced flow Non-Uniformity through the exchanger tubes. With the application of Computational Fluid Dynamics package FLUENT relative analysis pertaining to Non-uniform flow is carried out. The matter of interest of this paper is to analyze the heat transfer related to two mean temperatures namely cross-sectional and adiabatic mean temperature.