Exhaust Port Challenge

Objective:- To Perform a CHT analysis on an exhaust manifold.

1. Conjugate heat transfer analysis : The term conjugate heat transfer (CHT) is used to describe processes which involve variations of temperature within solids and fluids, due to thermal interaction between the solids and fluids. Conjugate heat transfer corresponds with the combination of heat transfer in solids and heat transfer in fluids. In solids, conduction often dominates whereas in fluids, convection usually dominates. Efficiently combining heat transfer in fluids and solids is the key to designing effective coolers, heaters, or heat exchangers. Forced convection is the most common way to achieve high heat transfer rate. In some applications, the performances are further improved by combining convection with phase change (for example liquid water to vapor phase change).

2. Performance od a CHT analysis on a model of an exhaust manifold

In this project we are going to find out the velocity , temperature and Coeffient of heat trasffer.

Geometry:

Case 1: Baseline solution

Mesh:

Mesh Quality:

Residual graph:

Temperature contour:

Velocity contour:

The velocity is max at outlet and minimum at inlet this shows that its due to the fact of mass conservation A1V1=A2V2 since inlet and outlet has same dia and all the fluid from the inlet exits at the same outlet, hence the velocity is maximum at outlet since all the fluid tries to flow through the one outlet hence mass conservation plays the role.

Contours of wall heat transfer Coeffient:

Due to an increase in velocity at the outlet Reynolds number increases , so the convective heat trasfer coeffient increased, Since forced convection involes Nusslet number is dependent on RE and Pr hence the heat transfer is higher at the outlet and especially where velocity is higher.

Case 2: Refined Mesh

In this case the setup is done with finer mesh and inflation layer at the inlet openigs.

Mesh:

Mesh Quality:

Temperature Contoufr:

Velocity Contour:

Contour of wall heat transfer coeffient: