Question: An engineer is to design an experimental apparatus that consists of a 25-mm-diameter smooth tube, where different fluids at 100°C are to flow through in fully developed laminar flow conditions. For hydrodynamically and thermally fully developed laminar flow of water, engine oil, and liquid mercury, determine
(a) the minimum tube length and
(b) the required pumping power to overcome the pressure loss in the tube at largest allowable flow rate.