Manufacturers of plate heat exchangers nowadays mainly offer plates with chevron corrugation patterns. The great influence of geometry parameters of chevron plates on fluid friction and heat transfer is the main reason to use these plates in plate heat exchangers. The main geometrical parameters are the inclination angle, profile shape of chevron corrugation and the aspect ratio of the profile. Nowadays sinusoidal profile is used for chevron profile shape. Corrugation of the chevron plates mixes the flow in channel intensively so that fluid flow becomes turbulent even in low Reynolds numbers.In this thesis plate heat exchanger channels with chevron plates for studying The effective geometrical parameters of flow (friction factor), such as chevron angles of plates, aspect ratio of chevron profile and compound channels, channels made from two chevron plates with different inclination chevron angle, has been modeled and the effective parameters is investigated. Moreover changing of flow nature between the chevron plates with respect to the inclination angle is studied. In order to examine the effect of aspect ratio of chevron profile on heat transfer, two plate heat exchangers with two different chevron angles inclusive three chevron plates has been simulated. In this research the continuity, momentum and energy equations are solved numerically by the aid of commercial computer code based on the finite volume method. After the study of various k-? turbulent models, the most appropriate k-? model for the numerical simulation of flow and heat transfer between the chevron plates has been determined. Because of the wide range of Reynolds numbers that are used in the flow section of this work, a wall function study is performed and at the end of each section the results of numerical simulation are validated with experimental results. This investigation shows that with inclination angle reduction of a plate heat exchanger channel plate with 60 degree chevron angle and making a compound channel, friction factor of fluid flow of compound channel reduces but by reducing chevron angle of plate step by step and in equal quantity in each step, the reduction of friction factor will not be equal in each step. the reduction of aspect ratio of channel plates of 60 degree chevron angle reduces the friction factor but in lower aspect ratio we can see more reduction in friction factor. On the other hand an increase in aspect ratio in chevron type plate heat exchanger channel plates with chevron angles of 30 degree and 60 degree will increase the heat transfer coefficient so that the more growth in aspect ratio will lead to the more growth in heat transfer coefficient. Key Words: Chevron type plate heat exchanger, Numerical simulation, Friction factor, Heat transfer, Flow distribution