(a) What is the basic function of heat exchanger? (3)

(b) Draw a line diagram showing the temperature gradient between the fluids at an intermediate heat conductive wall of a heat exchanger. (3)

(c) Explain with respect to flow pattern: (10)

(i) Parallel flow

(ii) Contraflow

(iii) Turbulent flow.

(iv) Streamline flow (for liquid inside tubes)