Segmental baffles in a $2-4$ shell and tube heat exchanger

1. change the flow pattern of the tube side fluid and increase the overall heat transfer co-efficient
2. increase the heat transfer coefficient in the shell side and support the tubes
3. help to reduce the thermal expansion of the tubes and increase the heat transfer coefficient in the tube side
4. increase the number of passes in the shell side and increase the heat transfer coefficient in the tube side