Comparitive study of mixing of two fluids in a mixing elbow and prediction of optimum length of the outlet section

The phenomena of heat transfer and fluid flow are very much evident in our daily life. Many industrial applications and manufacturing processes deal with fluid flow and heat transfer. The study of the flow of two different fluids in pipes and their mixing is also important from the design point of view in industrial application. The quality of the product mixture directly depends on the extent of heat transfer between the two fluids and their mixing. In the present study, a mixing elbow with two inlets has been considered for analysis. A mixing elbow is a device used to mix multiple fluids with different properties. The mixing elbow consists of at least two inlets and one outlet. The simulations have been carried out by varying the angle of one of the inlets (minor inlet, through which the hot fluid enters) which enhances the mixing of the two fluids resulting in desired quality (in terms of temperature) of the mixture at the exit, over a specified length of the pipe. Simulations have been carried out using ANSYS FLUENT software. The minor inlet angle has been varied from 0° to 90° and it has been observed that with an increased angle of the minor inlet, the desired quality of the mixture is obtained at shorter distances from the point of mixing. From these results, the minor inlet angle which gives the best results is chosen, and simulations are performed for that configuration by varying the temperature of the fluid entering the minor inlet from 40°C to 90°C in steps of 10 degree Celsius and the lengths of the outlet section are predicted using modern techniques like Predictive Modelling and Linear Regression. 3D graphs have been generated to study the distribution of temperature at various sections along the length of the pipe.