WL 308 Heat transfer in pipe flow
The convective heat transfer during pipe flow is determined by internal flow processes inside the tube and by heat conduction processes in the tube walls. With the WL 308 experimental unit, it is possible to study convective heat transfer on the pipe wall and inside the pipe of a tubular heat exchanger. Both parallel flow and counterflow mode with their different temperature curves are demonstrated in experiments.
The core element of the experimental unit is a double tube, which serves as the heat exchanger. Hot water is pumped through the inner tube. Cold water flows in the outer tube either in parallel flow or counterflow. The hot water emits part of its thermal energy to the cold water.
The non-linear temperature progression along the tubular heat exchanger is demonstrated by measuring the water temperatures in both tubes at the inlet, outlet and half of the transfer section. Measuring the tube wall temperature on the inner tube at half the transfer section allows the investigation of the convective heat transfer at the wall.
The closed hot water circuit contains a tank with electrical heater and a pump. Cold water is supplied and disposed of via the laboratory network. Valves are used to adjust the flow rate of hot and cold water.
The flow rate and all relevant temperatures are recorded and displayed on the experimental unit.
- model of a tubular heat exchanger
- heat exchanger can be operated in parallel flow and counterflow
- temperature measuring points on the inner tube wall and in the flow
- hot water circuit with temperature controller
Heat transfer surface
- average transfer surface: 0,013m2
Tube inner, copper
- 8x 1mm
Pump
- max. flow rate: 4m3/h
- max. head: 4m
Heater: 3kW, with overheating protection
Tank: 6,5L
Measuring ranges
- flow rate: 2x 20…250L/h
- temperature: 7x 0…100°C
230V, 50Hz, 1 phase
230V, 60Hz, 1 phase; 230V, 60Hz, 3 phases
UL/CSA optional
- convective heat transfer on tube walls and in the flow using the model of a tubular heat exchanger
- parallel flow or counterflow operation can be set via 3-way plug valves
- closed hot water circuit, insulated, with pump, heater and temperature controller
- constant flow rate of hot water via bypass setting
- flow rates adjustable via valves
- temperature sensors: inlet and outlet temperatures and after half of the transfer section
- additional measurement of the tube wall temperature at the inner tube after half of the transfer section
- flow meter for hot and cold water in each case
- record temperature curves
- in parallel flow mode
- in counterflow mode
- convective heat transfer on pipe walls and in the flow
- influence of mass flows on the temperature profile
- determining thermal balances
- determining the overall heat transfer coefficient
