0.45 kg/s of n-heptane is to be cooled from 100°c to 60°c in the annulus of a double pipe heat exchanger. the two steel pipes are 1/4 in and 2 in nominal size. a cooling stream of water, in the inner pipe, is available at a temperature of 27°c. calculate the mass flowrate of water required if the outlet temperature of water is 49°c, the overall heat transfer coefficient based on outside surface, and total surface area of the exchanger. if the effective exchanger length is not to exceed 10 ft, calculate the number of pipes required. also, do the calculations for both cocurrent flow and countercurrent flow. use reliable literature source for the physical properties. if the flow is in the transition region use hausen equation otherwise use the applicable seader and tate equation. ignore viscosity correction factor hint: if laminar flow persists it is a trial-and-error solution for length of the exchanger