An approach to study turbulent flow and conjugate heat transfer in tubes is proposed in this work. Instead of using the usual finite element or finite volume methods, this formulation applies a different technique that calculates both for the flow and heat transfer. It discretizes the flow in the radial direction using a fourth order finite differences method, which is more accurate than the traditional second order schemes. Using this technique, a system composed of several ordinary differential equations for the temperature and a set of linear equations for the velocities and pressure gradient is obtained. The equations are then integrated in the axial direction using a fourth order Runge-Kutta method. The values of viscosity, density and thermal conductivity are dependent on temperature, which makes the model suitable for the calculation of high temperature gradients, as in the case of refinery fired heaters. The turbulence is taken into account using a zero order turbulence model. A very interesting feature of this formulation is that for the laminar case the method is non-iterative, which makes it more desirable and faster than conventional computational fluid dynamics (CFB) packages.