Natural Convection Apparatus
Product Code : EL-HTL-11083
Quick answer: The natural convection apparatus measures the heat transfer coefficient for free convection from a heated vertical cylinder. A 38 mm OD, 500 mm brass pipe with an internal cartridge heater stands in a draught-free enclosure with a Perspex side, and seven thermocouples map its surface temperature. Lab Exports manufactures it in Delhi for engineering colleges, polytechnics and TVET institutes.
Specifications
| Component | Specification |
|---|---|
| Test pipe | Brass, 38 mm OD, 500 mm long, vertical |
| Heater | Internal cartridge heater |
| Thermocouples | 7 nos., along the pipe length |
| Enclosure | 200 x 200 x 800 mm, one side Perspex |
| Heater control | Dimmerstat |
| Power measurement | Voltmeter and ammeter |
| Temperature indicator | Multichannel digital |
| Services | 230 V, 5 A AC supply with earthing; bench area 1.5 x 0.75 m |
How the natural convection experiment is done
In natural convection there is no fan: air next to the hot pipe warms, becomes lighter and rises, and cooler air flows in to replace it. The heat transfer coefficient is found from h = Q / (A (Ts - Ta)), where Q is the heater input V x I, A the pipe surface area and Ts the mean of the thermocouple readings.
The result is compared with correlations of the form Nu = C (Gr Pr)^n, where the Grashof number Gr = g beta dT L^3 / nu^2 weighs buoyancy against viscosity. For laminar flow on a vertical surface Nu is about 0.59 (Gr Pr)^0.25. The seven thermocouples also show the surface temperature rising towards the top, where the boundary layer is thicker.
- Switch on the heater and set the input with the dimmerstat.
- Close the enclosure and wait for steady state.
- Record the voltmeter and ammeter readings, the seven surface temperatures and the room air temperature.
- Calculate h from the data and from the correlation.
- Repeat at other heater inputs.
Key features
- Vertical brass pipe, 38 mm OD and 500 mm long
- Internal cartridge heater with dimmerstat control
- Seven thermocouples along the pipe on a multichannel digital indicator
- Enclosure with a Perspex side keeps convection currents undisturbed
- Voltmeter and ammeter for the heat input
Documentation and supply
Installation instructions and a manual are supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the natural convection apparatus at its works in Laxmi Nagar, Delhi, and supplies it to engineering colleges, polytechnics and TVET institutes in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
Related Heat Transfer Lab products
- Pin Fin Apparatus (EL-HTL-11082)
- Forced Convection Apparatus (EL-HTL-11084)
- Critical Radius of Insulating Material (EL-HTL-11081)
- Specific Heat of Air Apparatus (EL-HTL-11085)
- Heat Pipe Apparatus (EL-HTL-11080)
- Heat Transfer in Agitated Vessel (EL-HTL-11087)
The full range is in the Heat Transfer Lab section of the Engineering Lab range.
Frequently asked questions
Why is the natural convection pipe enclosed?
The enclosure keeps room draughts away, so the air around the pipe moves only by buoyancy.
What does the natural convection apparatus measure?
The heat transfer coefficient for free convection from a heated vertical brass pipe at different heat inputs.
What is the price of the natural convection apparatus?
Prices are not published on the website. Add the natural convection apparatus to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-HTL-11083 and the quantity, to receive a quotation.
Does Lab Exports manufacture the natural convection apparatus?
Yes. Lab Exports manufactures the natural convection apparatus at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-HTL-11083.
Request a quote
Email [email protected] with the house code EL-HTL-11083 and the quantity, or add the natural convection apparatus to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.