Objective:
The objective of this numerical analysis is to design an Exhaust Gas Recirculation (EGR) cooler (Shell and tube heat exchanger) that must be compact with the following features: small volume, steady performance, easy to clean and durable in the high temperature.
Design Approach:
A CFD analysis has been performed for Shell and tube heat exchanger with segmental baffles and helical baffles. Shell and tube heat exchanger with segmental baffles is designed using Kern’s method to cool the EGR gas. Mass flow rate of air, fuel and exhaust gas temperature are measured for different load conditions of single cylinder DI diesel engine. For each helical and segmental baffle the percentage of EGR flow rate is varied from 14% to 20% of the exhaust gas. Assumptions are made by considering it as steady state flow, fluids at mean temperature and neglecting the leakage due to the gap between the tube and baffles.
Conclusion:
After the analysis predictions show accurate trend for change in EGR flow rate. The shell side pressure drop for heat exchanger with helical baffle is lower than the heat exchanger with segmental baffles. The flow in the shell side of the heat exchanger with conventional segmental baffles has dead zones because the fluid impacts right onto the wall perpendicularly. The flow in the shell side of the heat exchanger with helical baffles is smooth, rotational and helical due to the shape of the baffle, which results in decrease in pressure drop.
