LAB TECH SCIENTIFIC WORKS

Forced Convection Apparatus

Here’s a clear description of the Heat Transfer in Forced Convection Apparatus (commonly used in labs): ⸻ Heat Transfer in Forced Convection Apparatus The forced convection apparatus is designed to study the heat transfer characteristics of air when it is forced over a heated surface, such as a tube. It helps in determining the heat transfer coefficient under different air flow conditions. ⸻ Main Components: 1. Blower (Air Supply Unit): • A small centrifugal/axial blower is provided to supply air at different flow rates. • The velocity of air can be varied using a regulator. 2. Test Section (Heated Duct/Tube): • A horizontal metallic tube (usually made of copper or aluminum) is used as the test section. • An electric heater is fitted inside the tube to supply uniform heat. • Heat is transferred from the heater to the air flowing through the tube. 3. Heater & Control Unit: • Nichrome wire heater is wound inside the test section. • Electrical input to the heater is controlled using a variac/voltmeter-ammeter setup. • This provides known and adjustable heat input. 4. Temperature Sensors (Thermocouples): • Thermocouples are placed at different points along the test section to measure surface temperature of the tube. • One thermocouple measures inlet air temperature and another measures outlet air temperature. 5. Measuring Instruments: • Voltmeter and Ammeter → to measure electrical power supplied to the heater. • Manometer or Anemometer → to measure airflow rate. • Digital temperature indicator → to display thermocouple readings. 6. Insulation: • The test section is insulated with glass wool/ceramic wool to reduce heat loss to the surroundings. ⸻ Working Principle: • Air is forced through the test section by the blower. • The heater supplies a known amount of heat to the tube. • Heat is transferred from the tube wall to the flowing air by forced convection. • The rise in air temperature (difference between inlet and outlet) and the surface temperatures of the tube are measured. • From the data, the heat transfer coefficient (h) and Nusselt number (Nu) can be calculated for different airflow rates. ⸻ Applications: • To study the variation of heat transfer coefficient with Reynolds number. • To experimentally verify correlations for forced convection heat transfer. • Useful in understanding practical applications like cooling of electronic devices, heat exchangers, and HVAC systems

₹ 55,000Piece