Heat-transfer Flow-loop Station:
This apparatus has been developed to study the "Drug-reduction phenomena" associated with dilute polymer aqueous solutions which exhibit unprecedented drug reduction in turbulent flow (see related references). It could be adapted to study flow and heat transfer phenomena of other complex rheological fluids, including biological, electro-rheological smart fluids, nanofluids, and others.
Related Publications:
M. Kostic, "On Turbulent Drag and Heat Transfer Reduction Phenomena and Laminar Heat Transfer Enhancement in Non-Circular Duct Flow of Certain Non-Newtonian Fluids," Int. J. Heat & Mass Transfer, Vol.37, Suppl.1, p.133-147 (1994).
Go to: Kostic's Publications
* See Experimental Procedure *
The schematic diagram of already built heat-transfer flow-loop station is shown in the Figure. It consist of: a (re)circulation positive displacement pump (to minimize the fluid's mechanical degradation); a surge tank (to restrain vibrations); fluid reservoirs; a flow rate weighing (metering) platform, a collection equipment for measuring and calibrating flow rates; and appropriate piping and fittings. The station may accommodate more parallel test sections if needed, each with a calming and a mixing chamber. The existing instrumentation could be enhanced and computerized with new sensors and Data Acquisition (DAQ) system, to take advantage of the recent technological developments and PI’s involvement with research application of DAQ [19].
Test Section:
The 1.8X1.8 cm square test section, 7.6 m long (equivalent to 422 hydraulic diameters) consists of four walls. The two opposite walls, made of stainless steel plates (1.9X 0.6 cm cross-section, and 760 cm long), could be heated independently and (a)symmetrically by passing DC-electrical current through them. The other two opposite walls are made of transparent polycarbonate plates in order to allow flow visualization measurements. Special optical windows on the side walls are made to facilitate the Laser Doppler Velocity (LDV) measurements. More than one hundred thermocouples and seventeen pressure taps are positioned along the test section for local temperature and pressure measurements, respectively. The entrance to the test section is made sharp so that thermal and hydrodynamic entrance lengths develop simultaneously. Additional test sections could be easily added to the existing flow loop. For example, a 5:1 aspect ratio rectangular duct, with all walls made of polycarbonate transparent plastic suitable for flow visualization and the LDV measurements, may be fabricated and equipped with appropriate pressure taps and ports for flow visualization study.