DESCRIPTION

Technical Description

WL 308 is used to demonstrate the characteristic properties of heat transfer in a tubular heat exchanger. Tubular heat exchangers represent the simplest type of heat exchanger and are the preferred solution for transferring heat with high pressure differences or between high viscosity media (sludge). This type is also used to enable the temperature of the transported medium to be kept constant. 

The experimental unit features a pipe-in-pipe tube as the heat exchanger, a heated tank and pump for the hot water circuit, connections for the cold water circuit, and displays and controls. Hot water in the inner tube and cold water in the outer tube flow either in a parallel flow or in a counterflow. Part of the thermal energy of the hot water is transferred to the cold water. Valves are used to adjust the flow of hot and cold water. The cold water circuit is fed from the laboratory supply.

The non-linear temperature curve along a heat exchanger can be demonstrated by measuring the inlet and outlet temperatures as well as an additional temperature measuring point half way along the heat exchange path. During this process the water temperature in the inner and outer tubes is measured. Additional measurement of the inner tube wall temperature permits investigation of the heat transfer at the wall. 

In evaluation of the experiment key parameters such as the heat flux and heat transfer coefficient are determined.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- Heat balances
- Determining the heat transfer coefficient 
- Operation in parallel flow and counterflow
- Heat transfer on tube walls and in the flow
- Influence of the mass flow rate on the temperature curve