TH-3104 Free and Forced Convection Heat Exchanger

Measuring Device

  • Demonstration of the relationship between input and surface temperature in free convection.
  • Demonstration of the relationship between input and surface temperature in forced convection.
  • Demonstration of the use of extended surfaces to improve heat transfer from the surface.
  • To determine the temperature distribution along an extended surface.

Specifications

  • Investigate heat transfer in the air duct by forced convection.
  • Study of free convection.
  • Air duct with axial fan.
  • 3 heating elements with different geometries.
  • Continuously adjustable heating power and fan power.
  • Display of temperatures, heating power and air velocity.
  • Display of temperatures, heating power and air velocity in the software (if DAQ optional selected)
  • Microprocessor-based, data acquisition, system operation (optional)

Description

Heat transfer by Free & forced Convection in a vertical duct is carried out in this unit. Convection is one of the three basic types of heat transfer. In this process the whole fluid moved from warm zones into cold zones. The vertical duct is constructed in such a way that the air temperature and velocity can be readaily measured. A fan situated at the top of the duct provides the air stream for forced convection experiments. A control panel contains temperature measurement, power control and fan speed control circuits with appropriate instruments. Air velocity measured with portable anemometermounted on the duct.

Heat transfer by simultaneous conduction and convection, whether free or forced, forms the basis of most industrial heat exchanger and related equipment. The measurement and prediction of heat transfer coefficients for such circumstances is achieved in the Free & Forced Convection Heat Exchanger by studying the temperature profiles and heat flux in an air duct with associated flat and extended transfer surfaces. The vertical duct is so constructed that the air temperature and velocity can be readily measured, and a variety of .plug-in. modules of heated solid surfaces of known dimensions can be presented to the air stream for detailed study. A fan situated at the top of the duct provides the air stream for forced convection experiments.

A Control Panel contains temperature measurement, power control, and fan speed control circuits with appropriate instrumentation. Temperature measurement, to a resolution of 0.1oC is effected using thermocouple sensors with direct digital read-out in oC. Air velocity is measured with portable anemometer mounted on the duct. The power control circuit provides a continuously variable, electrical output of 0-100 watts with a direct read-outinwatts.

Using the instrumentation provided, free and forced convective heat transfer coefficients may be determined for:-

  1. A flat surface
  2. An array of cylinders (tuble bunddle)
  3. An extended finned surface
  4. A plate surface (optional)
  5. A cylinder (optional)
  6. A cylinder with heating foil to investagte local heat transfer (optional)

Each module may be used independently on the bench, to establish free convection coefficients for horizontal orientation.

Software TH-3104SW (optional)
DAQ software specially designed in National Instrument™, LABVIEW™ environment to measure and calculate the results of apparatus. The software is optional and while using software a set of electronic sensors are included. Software can be run with any Windows™ environment.