An interferometric study of free convective heat transfer at an indoor glazing with an insect screen attachment

Free convective heat transfer from an idealized window with an insect screen attachment was studied using a Mach-Zehnder interferometer. An experimental model was set up with an isothermal plate, two commercially available screens (KHP=8.74×10-9 m2, tHP=0.29 mm and KLP=3.40×10-9 m2, tLP=0.65 mm) and window to screen spacings of b=2 cm and b=1 cm. Heat transfer measurements using finite fringe interferograms were taken at a Rayleigh number of Ra=5.30×107 based on window height. Infinite fringe interferograms were taken for temperature field visualization. Screen temperature was also measured. Experimental results were compared to a preliminary CFD model developed with SolidWorks Flow Simulation and show good agreement. The results show that an insect screen produces a reduction in the convective heat transfer from the indoor glazing. The current measurements show that the effect of window to screen spacing is small. Results from this study are expected to be used for the validation of CFD models and for the development of correlations.

An interferometric study of free convective heat transfer at an indoor glazing with an insect screen attachment

Free convective heat transfer from an idealized window with an insect screen attachment was studied using a Mach-Zehnder interferometer. An experimental model was set up with an isothermal plate, two commercially available screens (KHP=8.74×10-9 m2, tHP=0.29 mm and KLP=3.40×10-9 m2, tLP=0.65 mm) and window to screen spacings of b=2 cm and b=1 cm. Heat transfer measurements using finite fringe interferograms were taken at a Rayleigh number of Ra=5.30×107 based on window height. Infinite fringe interferograms were taken for temperature field visualization. Screen temperature was also measured. Experimental results were compared to a preliminary CFD model developed with SolidWorks Flow Simulation and show good agreement. The results show that an insect screen produces a reduction in the convective heat transfer from the indoor glazing. The current measurements show that the effect of window to screen spacing is small. Results from this study are expected to be used for the validation of CFD models and for the development of correlations.

An interferometric study of free convection in a window with a heated between-panes blind

An experimental study has been conducted to examine free convection in a window with an enclosed aluminum Venetian blind. The unique feature of this experiment was that the blind slats were heated electrically to simulate absorbed solar radiation. Centre-glass convective heat transfer measurements and temperature field visualization were obtained using a laser Mach-Zehnder interferometer. Measurements were made for three plate (glazing) spacings, three blind slat angles, three blind heat fluxes, and two plate temperature differences. It was found that a recently proposed simplified model, called the Reduced Slat Length (RSL) model, closely predicted the experimental results when the flow appeared to be laminar and steady. Under these conditions, the temperature field and lateral heat transfer was dominated by conduction. Under some conditions, evidence of highly unsteady/turbulent flow was observed. As expected, the RSL model performed poorly under these conditions.

An interferometric study of free convection in a window with a heated between-panes blind

An experimental study has been conducted to examine free convection in a window with an enclosed aluminum Venetian blind. The unique feature of this experiment was that the blind slats were heated electrically to simulate absorbed solar radiation. Centre-glass convective heat transfer measurements and temperature field visualization were obtained using a laser Mach-Zehnder interferometer. Measurements were made for three plate (glazing) spacings, three blind slat angles, three blind heat fluxes, and two plate temperature differences. It was found that a recently proposed simplified model, called the Reduced Slat Length (RSL) model, closely predicted the experimental results when the flow appeared to be laminar and steady. Under these conditions, the temperature field and lateral heat transfer was dominated by conduction. Under some conditions, evidence of highly unsteady/turbulent flow was observed. As expected, the RSL model performed poorly under these conditions.

Interferometric Study of the Stability of K2CoxNi(1−x)(SO4)2·6H2O (KCNSH) Mixed Crystal Faces Depending on the Composition and Flow Velocity of the Solution

The change in the surface morphology of the (001) and (110) faces of K2CoxNi(1−x)(SO4)2·6H2O (KCNSH) mixed crystal, depending on the supercooling solution, has been studied under various conditions by laser interferometry. The experiments were carried out in both static mode, by changing the solution composition, and in dynamic mode, by changing the flow velocity. The conditions for the onset and suppression of the reaction of the isomorphic replacement leading to the formation of mosaic micro-inhomogeneity in mixed crystals have been studied. The mechanism of the reaction of isomorphic replacement has been analyzed depending on the shift of the solution composition from the initial one. For the first time, it has been observed that the reaction of isomorphic replacement may occur through a layer-by-layer mechanism.