## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Analysis of heat and mass transfer of the different moist object geometries with air slot jet impinging for forced convection drying

**ABSTRACT**

In the present work, the effect of the different geometric moist objects with straight and reverse semi-circular on the heat and mass transfer enhancement of the jet drying was conducted with a numerical analysis. The drying jet was a laminar 2D jet stationed at a constant jet distance (H) from the moist object. The diameter of the object, jet distance from the moist object and initial jet height were fixed in all cases. Temperature and mass distributions were obtained inside the object for different jet velocities. A finite volume method was used to solve the governing equations for momentum and energy by using ANSYS Fluent 17.0 software program. Calculations were performed for four different Reynolds numbers, namely, Re = 100, 200, 300 and 400. It was found good agreement with the experimental data available in the literature. The results showed that the geometry of straight semi-circular moist object had better performance of heat and mass transfer than that of the reverse moist object geometry. In addition, increasing Reynolds number showed a positive effect on heat and mass transfer. Locally, jet drying was found to be most effective near the stagnation point on the leading side of the objects.

**KEYWORDS**

PAPER SUBMITTED: 2016-07-21

PAPER REVISED: 2017-06-01

PAPER ACCEPTED: 2017-06-21

PUBLISHED ONLINE: 2017-07-08

- Martin, H., Heat and Mass Transfer Between Impinging Gas Jets and Solid Surfaces, Advances in Heat Transfer, 13 (1977), pp. 1-60.
- Lee, H.G., et al. A Numerical Investigation on the Fluid Flow and Heat Transfer in The Confined Impinging Slot Jet in the Low Reynolds Number Region For Different Channel Heights, International Journal of Heat and Mass Transfer, 51 (2008), 15-16, pp. 4055-4068.
- Tawfek, A.A., Heat Transfer Studies of The Oblique Impingement of Round Jets Upon A Curved Surface, Heat and Mass Transfer, 38 (2002), pp. 467-475.
- Olsson, E.E.M., et al. Flow and Heat Transfer From Multiple Slot Air Jets Impinging On Circular Cylinders, Journal of Food Engineering, 67 (2005), 3, pp. 273-280.
- Rahman, M.M., et al. Free Liquid Jet Impingement From a Slot Nozzle to A Curved Plate, Numerical Heat Transfer Part A, 57 (2010), 11, pp. 799-821.
- Gori, F., Bossi, L., Optimal Slot Height in the Jet Cooling of a Circular Cylinder, Applied Thermal Engineering, 23 (2003), 7, pp. 859-870.
- Gori, F., et al. Cooling of Two Smooth Cylinders in Row by A Slot Jet Of Air with Low Turbulence, Applied Thermal Engineering, 27 (2007), 14-15, pp. 2415-2425.
- Teamah, M.A., Khairat, M.M., Heat Transfer due to Impinging Double Free Circular Jets, Alexandria Engineering Journal, 54 (2015), 3, pp. 281-293.
- Hosain Md, L, et al. Heat Transfer by Liquid Jets Impinging on a Hot Flat Surface, Applied Energy, 164 (2016), pp. 934-943.
- McDaniel, C.S., Webb, B.W., Slot Jet Impingement Heat Transfer from Circular Cylinders, International Journal of Heat and Mass Transfer, 43 (2000), 11, pp. 1975-1985.
- Eren, H., et al. Nonlinear Flow and Heat Transfer Dynamics of Impinging Jets onto Slightly-Curved Surfaces, Applied Thermal Engineering, 27 (2007), 14-15, pp. 2600-2608.
- Frost, S.A., et al. Heat Transfer from a Flat Plate to a Turbulent Axisymmetric Impinging Jet, Proc. Inst. Mech. Eng., 211 (1997), 2, pp. 167-172.
- Chan, T.L, et al. Heat Transfer Characteristics of a Slot Jet Impinging on a semi-Circular Convex Surface, International Journal of Heat and Mass Transfer, 45 (2002), 5, pp. 993-1006.
- Chan, T.L., et al. Mean Flow and Turbulence Measurements of the Impingement Wall Jet on a Semi-Circular Convex Surface, Experiments in Fluids, 34 (2003), 1, pp. 140-149.
- Robinson, A., Schnitzler, E., An Experimental Investigation of Free and Submerged Miniature Liquid Jet Array İmpingement Heat Transfer, Experimental Thermal Fluid Science, 32 (2007), 1, pp. 1-13.
- Tarek, J.J., Ray, M.B., Application of Computational Fluid Dynamics for Simulation of Drying Processes: A Review, Drying Technology, 28 (2010), 2, pp. 120-154.
- Tarek, J.J., Ray, M.B., The Drying of Sludge in a Cyclone Dryer Using Computational Fluid Dynamics, Drying Technology, 29 (2011), 12, pp. 1365-1377.
- Kaya, A., et al. Numerical Modeling of Heat and Mass Transfer During Forced Convection Drying of Rectangular Moist Objects, International Journal of Heat and Mass Transfer, 49 (2006), 17-18, pp. 3094-3103.
- Alnak, D.E., et al. Simulation of Jet Drying of a Moist Cylinder at Low Reynolds Number, Drying Technology, 30 (2012), pp. 631-640.
- Kaya, A., et al. Experimental and Numerical Investigation of Heat and Mass Transfer During Drying of Hayward Kiwi Fruits (Actinidia Deliciosa Planch), Journal of Food Engineering, 88 (2008), 3, pp. 323-330.
- Hussain, M.M., Dincer, I., Two-Dimensional Heat and Moisture Transfer Analysis of a Cylindrical Moist Object Subjected to Drying: A Finite-Difference Approach, International Journal of Heat and Mass Transfer, 46 (2003), 21, pp. 4033-4039.
- Oztop, H.F., Akpinar, E.K., Numerical and Experimental Analysis of Moisture Transfer for Convective Drying of Some Products, International Communications in Heat and Mass Transfer, 35 (2008), 2, pp. 169-177.
- Kadem, S., et al. Computational Analysis of Heat and Mass Transfer During Microwave Drying of Timber, Thermal Science, 20 (2016), 5, pp. 1447-1455.
- Younsi, R., et al. Transient Analysis of Heat and Mass Transfer During Heat Treatment of Wood Including Pressure Equation, Thermal Science, 19 (2015), 2, pp. 693-702.
- FLUENT User's Guide Fluent Inc., Lebanon, (2003), NH.
- Varol, Y., et al. Numerical Analysis of Heat Transfer due to Slot Jets Impingement onto Two Cylinders with Different Diameters, International Communications in Heat and Mass Transfer, 39 (2012), pp. 726-735.
- Gori, F., et al. Cooling of Two Smooth Cylinders in Row by a Slot Jet of Air with Low Turbulence, Applied Thermal Engineering, 27 (2007), 14-15, pp. 2415-2425.