# H103G Water to Water Turbulent Flow Heat Exchanger

This is a highly advanced concentric tube heat exchanger with hot water flowing through the central tube while cooling water flows through the annular space. The heat exchanger has been divided into three equal sections in order to allow examination of the intermediate stream temperature conditions and temperature distribution through the heat exchanger.

Thermocouples sense the hot and cold stream temperatures at the four stations and the inner tube wall temperatures on entry and exit. The addition of the central tube surface temperatures at inlet and exit allow detailed investigation of the surface heat transfer coefficient inside and outside the central tube.

This allows advanced students to investigate the Nusselt, Reynolds, Prandtl relationship Nu = k Rea Prb.

Heat Exchanger: Concentric tube type with inlet, outlet and two intermediate measuring points plus pipe temperature.  Area 0.0288m2.

Water Heater: 3kW with electronic control .

Pump: Continuous rated to circulate hot water.

Flow Meters (1+1):- For hot and cold water.

Digital Thermometer: 0.1ºC resolution, with multi-way selector switch.

Cold water flow reversal valves(2): To establish concurrent and counter-current flow.

The PID temperature control on the H102 Heat Exchanger Service Unit allows investigation of turbulent flow conditions at a range of fixed Prandtl numbers.

Investigations using these two methods of control allow students to experimentally determine the constants in one of the classic empirical equations for turbulent heat transfer in a tube.

Nu = 0.023 Re0.8 Pr0.4

Requires the  H102-Heat-Exchanger-Service-Unit for operation.

• Determination of heat transfer rate, logarithmic mean temperature difference, overall heat transfer coefficient and 4 point hot and cold stream temperature profiles.
• Determination of surface heat transfer coefficient inside and outside the tube, and of the effect of fluid velocity.
• Comparison of performance in concurrent and in counter-current flow.
• Investigation of the relationship between Nusselt (Nu), Reynolds (Re) and Prandtl (Pr) Numbers for Reynolds Numbers up to 65000 and for Prandtl Numbers between 2.5 and 5.0.
• Determination of the constants in Nu = k Rea Prb.