Features
Demonstration of evaporation in a double-wall pipe evaporator made of glass
Operation with harmless, special low boiling point liquid system
Cooling circuit with water jet pump to generate negative pressure (vacuum)
Evaporation  circuit  with  CFC-free  evaporating liquid
During the generation of vapour, the medium that is to evaporate runs through different flow forms dependent on the heat transfer area. The medium flows into a tube evaporator as a single-phase fluid and exits the tube evaporator as single-phase superheated vapour. In practice, the water vapour generated in big systems is used e.g. for heating plants or machine drives. To design steam generators, it is important to have knowledge of the evaporation process with the boiling crises in order to ensure reliable operation. Boiling crises are caused by a sudden deterioration of the heat transfer, whereby the high heat flux density leads to a dangerous increase in the wall temperature.

Tesca Evaporation Process experimental unit can be used to examine and visualise the evaporation process in its various flow forms. This is done by heating evaporating liquid, in a tube evaporator made of glass. Compared with water, this liquid has the advantage that its boiling point is at 36,7°C (1013hPa), whereby the entire evaporation process takes place at much lower temperatures and a lower heating power. The pressure can be varied via the cooling circuit. Negative pressure (vacuum) can be generated by a water jet pump in the cooling circuit. The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Specifications
Visualization of evaporation in a tube evaporator
Heating and cooling medium: water
Tube evaporator made of double-wall glass
Heating circuit with heater, pump and expansion vessel
Safety valve protects against overpressure in the

Technical Specifications
Heater: power rating: 2kW; temperature range: 5...80°C
Heating and cooling medium: water
Pump: 3 stages; max. flow rate: 1,9m³/h; max. head: 1,5m
Power consumption: 58W
Tube   evaporator:   length:   1050mm;   inner diameter: 16mm; outer diameter: 24mm
Condenser: coiled tube made of copper

Measuring ranges
Pressure: -1...1,5bar relative
Temperature: 0...100°C

Experiments
Observation of typical forms of evaporation
Single phase liquid flow
Sub-cooled boiling
Slug flow
Annular flow
Film boiling
Dispersed flow
Single phase vapour flow
Wet steam 
Effect on the evaporation process by
Flow rate
Temperature
Pressure

Requirement in Laboratory:
Ÿ 230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase
Water connection: 500mbar, min. 320L/h; drain