Later, baffles are added to verify how they act on the thermal exchange efficiency. Study Domain The study domain is defined by shell-and-tube heat exchangers (Figure 1 and Figure 2).The results are compared to the heat exchanger design using the Transfer Unit Number (NUT) method to provide credibility to the mathematical modeling used. In the first one the domain dimensions are high-lighted, and in the second one the dimensions are the same to the previous.
The friction factor defined for flow in smooth tubes according to the correlation proposed by Petukhov  and valid for a range of Reynolds number of it is given by: (3) On the shell side, the correlation proposed by Mcadms  was used for: (4) where the Reynolds number is defined as the equivalent diameter on the shell side, which takes into consideration the wet perimeter and the free area for the flow.
The equivalent diameter varies according to the arrangement of tubes, which may be triangular or square, and is calculated by the equation below  : (5) where d (m) is the tubes outer diameter.
Given the effectiveness and the maximum exchange capacity, it is possible to find the heat transfer between the currents and the thermal conditions of both at the outlet of the shell and tube heat exchanger, as well as the Mean Logarithm of Temperature Differences (MLDT).
(13) where the temperature differences are defined by: (14) (15) For the method (MLDT) the dimensionless parameters P and R are determined: (16) (17) where R is the ratio of the fluids heat capacities and P represents the thermal effectiveness with respect to the cold fluid.
Some of them belong to technical literature, such as the Kern method  , which focuses mainly on the load losses and the laminar flow process, Bell  , which focuses on the experimental data being the best in relation to the literature methods and Tinker, which focuses on the flow division for the heat transfer analysis and loss of charge in each series.
Others occur through advanced software, which allows more accurate results, such as HTRI (Heat Transfer Research Inc, in USA) and HTFS (Heat Transfer and Fluid Flow Service, in England).The heat exchange process between two fluids that are at different temperature gradients and are separated by a solid wall occurs in many applications within the engineering, and the equipment for this process is called a heat exchanger.Heat transfer in a heat exchanger usually involves the convection process in each fluid and conduction through the wall separating the two fluids  .This project proposes the numerical reproduction development of the water flow in a shell-and-tube heat exchanger 2:1 according to the CLASS C TEMA standard (for moderate operation conditions, with commercial application).With baffles in aluminum and copper tube for the cold fluid flow, the shell is in acrylic, and with thermal analysis efficiencies with regard to the presence or not of the baffles, that is to analyze the efficiency with only, the tubes and the shell and soon after the analysis with tubes and baffles.In some cases, it is necessary to take into account the flux resistance exerted by fouling, both of the tube and the case, for the heat transfer overall coefficient.However, as treated water is used in the present study, these resistances are dispensed without causing great interference to the design.Heat exchangers are widely used equipment on an industrial and commercial scale, the application of these equipments on an industrial scale represents innovative processing solutions reflecting the processes efficiency, producing significant savings and lower cost, supporting the business success, and consequently offering opportunities, social responsibility, which are the pillars of sustainability.For the development of this work the methodology was used to calculate effectiveness, following the design parameters and contour conditions, it was analyzed the fluids behavior in the shell and the tube, through computational fluid dynamics (CFD) using the software ANSYS CFX 15.0.Given their wide use on an industrial scale, heat exchangers are highly important equipment in any global scenario, as they are responsible for the greatest energy demands, as well as they are process equipment, responsible for all industry processing such as footwear, beverage and other industries.Their wide spread application can be attributed to ease of manufacture from a variety of materials.