## THERMAL SCIENCE

International Scientific Journal

### EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION IN AN ENCLOSURE WITH PARTIAL PARTITIONS AT DIFFERENT ANGLES

**ABSTRACT**

Natural convection heat transfer in a partially partitioned enclosure has been investigated experimentally using Mach-Zehnder Interferometry technique. The top and bottom of the enclosure are insulated while one of the vertical walls is heated isothermally. The partitions are made of wood fiber and are attached to the heated wall with angles changing from 30° to 150° in different experiments. The length of each partition is equal to the width of the enclosure, therefore dividing the enclosure to isolated cells only at 90°. At other angles the cells are interconnected near the cold wall. Rayleigh number based on the enclosure width is changed from 3500 to 32000. Results for the local and the average Nusselt numbers at the heated wall of the enclosure are presented and discussed for various partition angles and Rayleigh numbers. It is found that, at each Rayleigh number, there exists an optimum inclination angle which minimizes the average Nusselt number.

**KEYWORDS**

PAPER SUBMITTED: 2012-05-26

PAPER REVISED: 2013-02-12

PAPER ACCEPTED: 2013-02-11

PUBLISHED ONLINE: 2013-04-13

**THERMAL SCIENCE** YEAR

**2014**, VOLUME

**18**, ISSUE

**4**, PAGES [1133 - 1144]

- Alhazmy, M., Numerical investigation on using inclined partitions to reduce natural convection inside the cavities of hollow bricks, International Journal of Thermal Sciences, 49 (2010), pp. 2201-2210.
- Fontana, L., da Silva, A., Mariani, V., and Marcondes, F., The influence of baffles on the natural convection in trapezoidal, Numerical Heat Transfer, Part A, 58 (2010), pp. 125-145,
- Wu1, W., and Ching, C. Y., Laminar natural convection in a square cavity with a partition on the heated vertical, Experimental Heat Transfer, 23 (2010), pp.:298-316.
- Sharma, A., Pradeep, A., Velusamy, K., Chellapandi, P., Raj, B., Interaction of natural convection flow in multiple open cavities formed due to horizontal fins, Annals of Nuclear Energy, 38 (2011), pp. 1906-1915.
- Paroncini, M., Corvaro, F., Montucchiari, A., Nardini, G., A numerical and experimental analysis on natural convective heat transfer in a square enclosure with partially active side walls, Experimental Thermal and Fluid Science, 36 (2012), pp. 118-125.
- Tong, T. W. and Gerner, F. M., Natural Convection in Partitioned Air Filled Rectangular Enclosure, International Communications in Heat and Mass Transfer, 13 (1986), pp. 99-108.
- Shiraishi, T. M., Nagasawa, F. and Kawamura, Y., Natural Convention Heat Transfer in Enclosures with Multiple Vertical Partitions, Int. Journal of Heat and Mass Transfer, 31 (1988), pp. 1679-4686.
- Acharya, S. and Jetli, R., Heat Transfer due to Buoyancy in a Partially Divided Square Box, Int. J. Heat Mass Transfer, 33 (1990), pp. 931-942.
- Ampofo, F., Turbulent Natural Convection of Air in a Non-partitioned or Partitioned Cavity with Differentially Heated Vertical and Conducting Horizontal Walls, Experimental Thermal and Fluid Science, 29 (2005), pp. 137-157.
- Ben-Nakhi, A. and Chamkha, A. J., Effect of Length and Inclination of a Thin Fin on Natural Convection in a Square Enclosure, Numerical Heat Transfer, Part A: Applications, (2006), pp. 381-399.
- Frederick, R.L. and Valencia, A., Heat Transfer in a Square Cavity with a Conducting Partition on its Hot Wall, Int. Commun. Heat Mass Transfer, 16 (1989), pp. 347-354. 15
- Frederick, R. L., Natural Convection in an Inclined Square Enclosure with a Partition Attached to its Cold Wall, Int. J. Heat Mass Transfer, 32 (1989), pp. 87-94.
- Facas, G.N., Natural Convection in a Cavity with Fins Attached to Both Vertical Walls, J. Thermophys. Heat Transfer, 7 (1993), pp. 555-560.
- Nowak, E. S. and Novak, M. H., Vertical Partitions in Slender Rectangular Cavities, Int. J. Heat and Fluid Flow, 15 (1994).
- Lakhal, E.K., Hasnaoui, M., Bilgen, E., Vesseur, P., Natural Convection Heat Transfer in Rectangular Enclosures with Perfectly Conducting Fins Attached on the Heated Wall, Proc. Int. Heat Transfer Conf., Brighton, UK, (1994), pp. 97-102.
- Bilgen, E., Natural Convection in Cavities with a Thin Fin on the Hot Wall, International Journal of Heat and Mass Transfer, 48 (2005), pp. 3493-3505.
- Mezrhab, A., Jami, M., Abid, C., Bouzidi, M., Lallemand, P., Lattice-Boltzmann Modelling of Natural Convection in an Inclined Square Enclosure with Partitions Attached to its Cold Wall, Int. J. Heat Fluid Flow, 27 (2006), pp. 456-465.
- Jami, M., Mezrhaba, A., Bouzidib, M., Lallemand, P., Lattice-Boltzmann Computation of Natural Convection in a Partitioned Enclosure with Inclined Partitions Attached to its Hot Wall, Physica A, 368 (2006), pp. 481-494.
- Varol, Y., Oztop, H. F., Ozgen, F., Koca A., Experimental and numerical study on laminar natural convection in a cavity heated from bottom due to an inclined fin, Heat Mass Transfer, 48 (2012), pp. 61-70.
- Oztop, H. F., Varol, Y., Koca, A., Mujdat Firat, Experimental and numerical analysis of buoyancy-induced flow in inclined triangular enclosures, International Communications in Heat and Mass Transfer, 39 (2012), pp. 1237-1244.
- Varol, Y., Oztop, H. F., and Pop, I., Natural convection in porous media-filled triangular enclosure with a conducting thin fin on the hot vertical wall, Proc. IMechE Vol. 222 Part C: J. Mechanical Engineering Science
- Varol, Y., Natural convection in porous triangular enclosure with a centered conducting body, International Communications in Heat and Mass Transfer, 38 (2011), pp. 368-376.
- Lin, C., Yang, H., Zhu, Z., Numerical exploration of 1+2 type laminar natural convection in a differentially heated square cavity using Chebyshev spectral collocation method, International Communications in Heat and Mass Transfer, 39 (2012), pp. 593-597.
- Huelsz, G., Rechtman, R., Heat transfer due to natural convection in an inclined square cavity using the lattice Boltzmann equation method, International Journal of Thermal Sciences, 65 (2013), pp. 111-119.
- Jourabian, M., Farhadi, M., Sedighi, K., Rabienataj Darzi, A. and Vazifeshenas, Y., Simulation of natural convection melting in a cavity with fin using lattice Boltzmann method, Int. J. Numer. Meth. Fluids, 70 (2012), pp. 313-325.
- Hauf, W. and Grigull, U., Optical Methods in Heat Transfer, Advances in Heat Transfer, 6 (1970), pp. 133-366
- Eckert, E.R.G., Goldstein, R.J., Measurements in Heat Transfer, second ed., McGraw-Hill, (1972), pp. 241-293.
- Jakob, M., Free Heat Convection Through Enclosed Plane Gas Layers, J. Heat Transfer, 193 (1964).
- Mull, W. and Reiher, H., Der Warmeschutz van Luftschiten, Beih. Gevrtndh.-lngrl , 28 (1930).
- Eckertf, E.G. and Carlson, W. O., Natural Convection in a Layer Enclosed Between Two Vertical Plates with Different Temperatures, International Journal of Heat and Mass Transfer (1961), pp. 106-110.