A counter-flow heat exchanger is used to cool water from 60°C to 20°C. The water flows at 0.2 m/s through the inner tube and the cooling fluid flows in the enclosure. The inner tube is 6-cm in diameter and 15-m in length. It is thin and made of copper. The flow rate of the cooling fluid is 1.2 kg/s and convection coefficient is 360 W/m².°c. The specific heat of the cooling fluid is 1600 J/kg. °C. The surface temperature of the inner tube can be approximated as almost isothermal. (a) What is the mass flow rate of water? 0.56 kg/s (b) What is the effectiveness of this heat exchanger? 0.285

A liquid food flows in the inner pipe (internal diameter-8 cm) of a double-pipe heat exchanger. The liquid food (p=1200 kg/m and C,-4 kJ/kgK) flows at 0.055 m/min and enters the heat exchanger at 6°C and exits at 38°C. In the annular section, water at 96°C enters the heat exchanger and flows countercurrently at an average flow rate of 1 kg/s (average Cp= 4.18 kJ/kgK). a) Sketch a graph showing the temperature profile of the heating water and quid food through the heat exchanger. Clearly label the two streams and draw arrows to indicate the flow directions of liquid food and water. i) ii) Calculate the mass flow rate (kg/s) of the liquid food. ii) Me sure the temperature (°C) of the exiting water stream. iv) Calculate the log-mean temperature difference for this system. Estimate the length (m) of this pipe heat exchanger that needs to be constructed in order to achieve an overall heat transfer coefficient of 2.5 W/m2K.

In order to cool a mass flow rate of 25 Kg/h of air (cp = 1060 J/Kg oC)  at 300 oC, it is passed through the tube side of a counter flow heat exchanger with a length of 2 m and 2.54 cm tube outer diameter. The cooling water, (cp = 4182 J/Kg oC and  r  = 1000 Kg/m3), enters the heat exchanger at a temperature of 30 oC with a volume flow rate of 0.3 Litre/min. If the overall heat transfer coefficient, U, is 5.83 W/m2 oC and the effectiveness of the heat exchanger 60 %, calculate the following: The heat transfer rate, The exit temperatures of both the water and the air, The surface area of the heat exchanger, The number of tubes used in the heat exchanger The capacity rate ratio.

A shell-and-tube heat exchanger with two-shell passes and 4-tube passes is used for cooling oil (cp = 2.0 kJ/kg·K) from 125°C to 55°C. The coolant is water, which enters the shell side at 25°C and leaves at 46°C. The overall heat transfer coefficient is 900 W/m2·K. For an oil flow rate of 10 kg/s, calculate the cooling water flow rate and the heat transfer area.