Film & Dropwise Condensation | ThermoFlux – 7097
The Film & Dropwise Condensation ThermoFlux – 7097 is a laboratory unit for the visualisation and investigation of both filmwise and dropwise condensation within a transparent glass cylinder test section. It features two water-cooled condenser tubes in copper and brass alloys (15 mm diameter, 95 mm effective length): one gold-plated for dropwise condensation and one natural finish for filmwise condensation. This film and dropwise condensation unit includes a 3 kW electric heater with temperature controller, a water jet vacuum ejector, six thermocouples (-100 to 400°C), a pressure gauge (0 to 6 kg/cm²), two rotameters, and a pressure switch with safety valve. Optional LabVIEW-based DAQ software is available for Windows-based data acquisition and result processing.
The Film & Dropwise Condensation ThermoFlux – 7097 is a laboratory unit specially designed to enable students to visualise and investigate both filmwise and dropwise condensation processes within a transparent glass test section. This film and dropwise condensation unit includes two water-cooled copper and brass condenser tubes with different surface treatments, a 3 kW controlled heater, a water jet vacuum ejector, six thermocouples, two rotameters, and a pressure gauge for comprehensive condensation heat transfer analysis.
Product Overview
The Film & Dropwise Condensation ThermoFlux – 7097 is built around a transparent glass cylinder test section that allows direct visual observation of the condensation process. Two water-cooled condenser tubes are installed inside the tank: one with a gold-plated surface to realise dropwise condensation and one with a natural finish surface to realise filmwise condensation. Both condensers are fabricated from copper and brass alloys, have a diameter of 15 mm and an effective length of 95 mm, and are each fitted with a thermocouple.
In filmwise condensation, a film of condensate forms and spreads over the wettable natural finish surface, increasing in thickness as vapour continues to condense. This liquid film acts as a poor thermal conductor, contributing to thermal resistance. In dropwise condensation, the non-wettable gold-plated surface causes condensate to form as spherical beads that grow, coalesce, and flow downward, leaving bare surface areas with very low thermal resistance and enabling high heat fluxes.
A 3 kW electric heater with a temperature controller adjusts the boiling temperature within the tank. A water jet vacuum ejector evacuates the tank to enable operation at sub-atmospheric pressures. A pressure switch and safety valve are fitted for safe operation. Six thermocouples with a digital temperature indicator (range: -100 to 400°C) measure temperatures across the system. A pressure gauge with a range of 0 to 6 kg/cm² measures tank pressure. Two rotameters measure the cooling water flow rates for both condensers independently.
Film & Dropwise Condensation ThermoFlux – 7097, Technical Specifications
| Parameter | Value |
|---|---|
| Test Section | Glass cylinder, transparent |
| Condenser Count | 2 |
| Condenser Surface 1 | Gold-plated (dropwise condensation) |
| Condenser Surface 2 | Natural finish (filmwise condensation) |
| Condenser Material | Copper and brass alloys |
| Condenser Diameter | 15 mm |
| Condenser Effective Length | 95 mm |
| Condenser Thermocouples | 1 per condenser |
| Heater Power | 3 kW |
| Heater Type | Electrical, with temperature controller |
| Vacuum System | Water jet vacuum ejector |
| Safety Devices | Pressure switch, safety valve |
| Number of Thermocouples | 6 |
| Temperature Measuring Range | -100 to 400°C |
| Pressure Gauge Range | 0 to 6 kg/cm² |
| Flow Measurement | 2 rotameters, one per condenser |
Technical Data
Condensers
| Parameter | Value |
|---|---|
| Number | 2 |
| Surface Type 1 | Gold-plated |
| Surface Type 2 | Natural finish |
| Material | Copper and brass alloys |
| Diameter | 15 mm |
| Effective Length | 95 mm |
| Thermocouples | 1 per condenser |
Heater
| Parameter | Value |
|---|---|
| Power | 3 kW |
| Type | Electrical |
| Control | Temperature controller |
Test Section
| Parameter | Value |
|---|---|
| Material | Glass cylinder |
| Purpose | Visualisation of condensation process |
Instrumentation
| Parameter | Value |
|---|---|
| Thermocouples | 6, with digital temperature indicator |
| Temperature Range | -100 to 400°C |
| Temperature Controller | 1, for heater |
| Rotameters | 2, one per condenser |
| Pressure Gauge Range | 0 to 6 kg/cm² |
Vacuum System
| Parameter | Value |
|---|---|
| Type | Water jet vacuum ejector |
| Purpose | Tank evacuation |
Safety Devices
| Parameter | Value |
|---|---|
| Pressure Switch | 1 |
| Safety Valve | 1 |
Key Features
- Film and Dropwise Condensation Unit Type: Transparent glass cylinder test section for direct process visualisation
- Condensers: 2 water-cooled tubes, copper and brass alloys, 15 mm diameter, 95 mm effective length
- Condenser Surfaces: Gold-plated (dropwise) and natural finish (filmwise), one thermocouple each
- Heater: 3 kW electric heater with temperature controller for boiling temperature adjustment
- Vacuum System: Water jet vacuum ejector for tank evacuation
- Temperature Measurement: 6 thermocouples with digital indicator, -100 to 400°C
- Pressure Measurement: Pressure gauge, 0 to 6 kg/cm²
- Flow Measurement: 2 rotameters, one per condenser
- Safety Devices: Pressure switch and safety valve
- Nucleate Boiling: Visual observation also supported
- Dalton’s Law: Demonstration supported
- Saturation Pressure-Temperature Relationship: Investigation for water up to 100°C
- Effect of Air in Condensers: Study supported
- Software: Optional LabVIEW-based DAQ software, Windows compatible
Experiments
- Visual observation of filmwise and dropwise condensation, as well as nucleate boiling
- Determination of heat flux and heat transfer coefficients in both filmwise and dropwise condensation at different operating pressures
- Demonstration of Dalton’s Law
- Investigation of the relationship between saturation pressure and temperature for water up to 100°C
- Study of the effect of the presence of air in the condensers
Construction and Design
The Film & Dropwise Condensation ThermoFlux – 7097 is constructed around a transparent glass cylinder test section that provides unobstructed visualisation of the condensation process. Two water-cooled condenser tubes fabricated from copper and brass alloys are installed inside the tank. Each tube measures 15 mm in diameter with an effective length of 95 mm. One tube has a gold-plated surface to produce dropwise condensation on the non-wettable surface, and the other has a natural finish surface to produce filmwise condensation on the wettable surface. Each condenser is fitted with a thermocouple. A 3 kW electric heater with a temperature controller is fitted to adjust and maintain the boiling temperature within the tank. A water jet vacuum ejector evacuates the tank for sub-atmospheric pressure operation. A pressure switch and a safety valve are fitted for safe operation.
Six thermocouples with a digital temperature indicator cover a measurement range of -100 to 400°C across the system. A pressure gauge measures tank pressure from 0 to 6 kg/cm². Two rotameters independently measure the cooling water flow rates for each condenser. This film and dropwise condensation unit enables direct comparison of both condensation modes under identical operating conditions with full instrumentation for heat flux and heat transfer coefficient determination.
Software
ThermoFlux – 7097 Software (Optional)
- Developed in the National Instruments LabVIEW environment
- Designed specifically for data acquisition with this apparatus
- Measures, processes, and stores experimental results on a PC
- A set of electronic sensors is included when the software option is selected
- Compatible with any Windows operating system
Scope of Delivery
- 1 experimental unit
- 1 instructional manual
Q1: What is the difference between the two condenser tubes in the Film & Dropwise Condensation ThermoFlux – 7097?
One condenser tube has a gold-plated non-wettable surface that produces dropwise condensation, where condensate forms as spherical beads with low thermal resistance. The other has a natural finish wettable surface that produces filmwise condensation, where a continuous liquid film forms and acts as a poor thermal conductor. Both tubes are fabricated from copper and brass alloys, measure 15 mm in diameter with an effective length of 95 mm, and are each fitted with a thermocouple.
Q2: How is the tank pressure controlled and monitored in this film and dropwise condensation unit?
A water jet vacuum ejector evacuates the tank to enable operation at sub-atmospheric pressures. Tank pressure is monitored using a pressure gauge with a range of 0 to 6 kg/cm². A pressure switch and a safety valve are fitted for safe operation.
Q3: How many temperature measurement points does the unit provide?
Six thermocouples are provided with a digital temperature indicator covering a range of -100 to 400°C. Each condenser tube also carries its own thermocouple. A separate temperature controller manages the heater.
Q4: How are cooling water flow rates measured for each condenser?
Two rotameters are included, one for each condenser, enabling independent measurement and control of the cooling water flow rate through each condenser tube.
Q5: Is the DAQ software included as standard?
No. The ThermoFlux – 7097 DAQ software is optional. When selected, it includes the required electronic sensors, processes and stores experimental data on a PC, and runs in a LabVIEW environment on any Windows operating system.
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