The Flow Boiling Demonstration Unit, "TFEB", has as main component an experimental tube made of two glass concentric tubes. In thesetubes two fluids flow crosscurrent: refrigerant, which flows by convection and in an ascendant way through the internal tube, and hot water,which flows in a descendant way through the external tube. This unit has been designed for using SES36 refrigerant gas, free of CFC´s,compatible with the Environment.
The main circuit will be where the different stages of the two-phase flow will be visualised by student. This circuit is composed of:
- Internal glass concentric tube, where the refrigerant liquid flows.
- Regulation valve for the input flow to the experimental tube.
- Condensing chamber, that is complemented with a pressure meter which allows to determine the presence of air in the system, asecurity valve to protect it from possible over pressure. With a temperature sensor the refrigerant temperature into the tank will bevisualized. Other temperature sensor shows the temperature of the saturated vapour in the condensing chamber.
Basically, this second circuit is composed of:
- External glass concentric tube, through which hot water flows to transfer the hot to the internal tube fluid.
- Thermostatic bath, with a resistance of 600 W. It heats the water in the tank.
- Centrifugal pump for recirculation.
The electric power consumed by the resistance is controlled throught the thermostatic bath itself.
The heat transfer can be valued because there are two temperature sensors in the refrigerant liquid, in the input and in the output of theconcentric tubes.
Finally the condensing chamber has a security valve. It also can be used if we want to carry out the refrigerant charge operation.