Analysis of natural convection in a square cavity with a thin partition for linearly heated side walls (original) (raw)
Related papers
Thermal Science, 2014
In the present paper, natural convection fluid flow and heat transfer in a square cavity heated from below and cooled from sides and the ceiling with a thin fin attached to its hot bottom wall is investigated numerically. The right and the left walls of the cavity, as well as its horizontal top wall are maintained at a constant temperature T c , while the bottom wall is kept at a constant temperature T h ,with T h > T c. The governing equations are solved numerically using the finite volume method and the couple between the velocity and pressure fields is done using the SIMPLER algorithm. A parametric study is performed and the effects of the Rayleigh number and the length of the fin on the flow pattern and heat transfer inside the cavity are investigated. Two competing mechanisms that are responsible for the flow and thermal modifications are observed. One is the resistance effect of the fin due to the friction losses which directly depends on the length of the fin, whereas the other is due to the extra heating of the fluid that is offered by the fin. It is shown that for high Rayleigh numbers, placing a hot fin at the middle of the bottom wall has more remarkable effect on the flow field and heat transfer inside the cavity.
International Journal of Engineering Science, 2005
A penalty finite element analysis with bi-quadratic rectangular elements is performed to investigate the influence of uniform and non-uniform heating of wall(s) on natural convection flows in a square cavity. In the present investigation, one vertical wall and the bottom wall are uniformly and non-uniformly heated while the other vertical wall is maintained at constant cold temperature and the top wall is well insulated. Parametric study for a wide range of Rayleigh number (Ra), 10 3 6 Ra 6 10 6 and Prandtl number (Pr), 0.2 6 Pr 6 100 shows consistent performance of the present numerical approach to obtain the solutions as stream functions and temperature profiles. Heat transfer rates at the heated walls are presented in terms of local Nusselt number.
Natural Convection in a Square Cavity with Discrete Heating at the Bottom with Different Fin Shapes
Heat Transfer Engineering, 2017
Numerical study is carried out to investigate the effect of different fin shapes on heating a square cavity by small heating strip located at the bottom wall. The natural convection of air is considered with constant heat flux from heat source which is located at the centre of the bottom wall. The width of the heating strip is assumed to be 20% of the total width of the bottom wall. The remaining (non-heated) part of the bottom wall and the top wall are adiabatic and the side walls are maintained at constant temperature. The investigation considered four shapes of
Effects of fin on mixed convection heat transfer in a vented square cavity: A numerical study
Mağallaẗ al-qādisiyyaẗ li-l-ʻulūm al-handasiyyaẗ, 2023
Numerical investigation of mixed convective in a vented square cavity with fin. The horizontal walls are adiabatic, while the left and right walls are hot (ℎ) and cold () temperatures, respectively. The fluid inlet to the cavity from the lower left open area(), and exits from the upper right open area (). In this study, a finite element scheme is employed. The analysis is done for specific Prandtl number (= 7), Reynolds number (50 ≤ ≤ 200), fin length (0.2 ≤ ≤ 0.6), Richardson number (0.1 ≤ ≤ 1), and the location of the fin (0.2 ≤ ℎ ≤ 0.6). The finding indicates that the increases when high the location of the fin increases at the maximum height of this fin location is estimated to be 17% due to an increase in the fluid flow area on the hot wall caused by rising convective. The highest heat transfer occurs when the fin length equals 0.6 at the location(ℎ = 0.2).
Journal of Mechanical Science and Technology, 2015
Finite element method was used to investigate the effects of heater location and heater size on the natural convection heat transfer in a 2D square cavity heated partially or fully from below and cooled from above. Rayleigh number (5Í10 2 ≤ Ra ≤ 5Í10 5), heater size (0.1 ≤ D/L ≤ 1.0), and heater location (0.1 ≤ x h /L ≤ 0.5) were considered. Numerical results indicated that the average Nusselt number (Nu m) increases as the heater size decreases. In addition, when x h /L is less than 0.4, Nu m increases as x h /L increases, and Nu m decreases again for a larger value of x h /L. However, this trend changes when Ra is less than 10 4 , suggesting that Nu m attains its maximum value at the region close to the bottom surface center. This study aims to gain insight into the behaviors of natural convection in order to potentially improve internal natural convection heat transfer.
Heat Transfer Research, 2011
Fluid flow and natural convection heat transfer in a differentially heated square cavity with a fin attached to its cold wall is investigated numerically. The top and the bottom horizontal walls of the cavity are insulated while the left and right vertical walls of the cavity are maintained at a constant temperature T h and T c , with T h > T c , respectively. The governing equations written in terms of the primitive variables are solved numerically using the finite volume method and the SIMPLER algorithm. Using the developed code, a parametric study is performed, and the effects of the Rayleigh number, length of the fin and its position on the flow pattern and heat transfer inside the enclosure are investigated. The results show that for high Rayleigh numbers, a longer fin placing at the middle of the right wall has a more remarkable effect on the flow field and heat transfer inside the cavity.
Effect of inclined thick fin on natural convection in a cavity heated from bottom
Progress in Computational Fluid Dynamics, An International Journal, 2015
In this study, natural convection heat transfer in a square cavity with an adiabatic fin mounted on a vertical wall was investigated numerically. Vertical boundaries were adiabatic and horizontal boundaries were isothermal at different constant temperature. Two-dimensional equations of conservation of mass, momentum and energy were solved using finite difference method. Successive under relaxation (SUR) method was used to solve linear algebraic equations. Results were obtained for various geometrical parameters as the thermal conductivity ratio (RK = 0.1, 1.0 and 10), inclination angle of the fin (30° ≤ φ ≤ 150°), thickness of the fin (0.033 ≤ t ≤ 0.2), and Rayleigh numbers (10 3 ≤ Ra ≤ 10 6). Location and length of fin was fixed as h = w = 0.5. Results were presented with streamlines, isotherms, local and mean Nusselt numbers. It was found that Rayleigh number and the fin mounted on the wall had significant effect on natural convection heat transfer and flow field. The thick fin can be used as control parameter of heat and fluid flow.
Heat and Mass Transfer, 2011
Natural convection heat transfer in an inclined fin attached square enclosure is studied both experimentally and numerically. Bottom wall of enclosure has higher temperature than that of top wall while vertical walls are adiabatic. Inclined fin has also adiabatic boundary conditions. Numerical solutions have been done by writing a computer code in Fortran platform and results are compared with Fluent commercial code and experimental method. Governing parameters are Rayleigh numbers (8.105 ≤ Ra ≤ 4 × 106) and inclination angle (30° ≤ and ≤ 120°). The temperature measurements are done by using thermocouples distributed uniformly at the wall of the enclosure. Remarkably good agreement is obtained between the predicted results and experimental data. A correlation is also developed including all effective parameters on heat transfer and fluid flow. It was observed that heat transfer can be controlled by attaching an inclined fin onto wall.
Natural Convection at Different Prandtl Numbers in Rectangular Cavities with a Fin on the Cold Wall
The natural convection in differentially heated rectangular cavities with a fin attached to the cold wall was investigated numerically. The top and the bottom horizontal walls of the cavities were insulated while their left and the right vertical walls were maintained at a constant temperature Th and Tc, respectively with Th > Tc. The governing equations written in terms of the primitive variables were solved numerically using the finite volume method while the velocity and pressure fields were coupled using the SIMPLER algorithm. Using the developed code effects of pertinent parameters such as length and location of fin, aspect ratio of the enclosure, Rayleigh number, and Prandtl number on heat transfer and fluid flow in the enclosure were investigated. The results showed that for the cavity filled with water, at high Rayleigh numbers, a longer fin placing at the middle of the right wall has more remarkable effect on the heat transfer inside the cavity. Also, it was observed tha...
Journal of Naval Architecture and Marine Engineering, 2011
In this study natural convection flow in a square cavity with heat generating fluid and a finite size heater on the vertical wall have been investigated numerically. To change the heat transfer in the cavity, a heater is placed at different locations on the right vertical wall of the cavity, while the left wall is considered to be cold. In addition, the top and bottom horizontal walls are considered to be adiabatic and the cavity is assumed to be filled with a Bousinessq fluid having a Prandtl number of 0.72. The governing mass, momentum and energy equations along with boundary conditions are expressed in a normalized primitive variables formulation. Finite Element Method is used in solution of the normalized governing equations. The parameters leading the problem are the Rayleigh number, location of the heater, length of the heater and heat generation. To observe the effects of the mentioned parameters on natural convection in the cavity, we considered various values of heater locations, heater length and heat generation parameter for different values of Ra varying in the range 102 to 105. Results are presented in terms of streamlines, isotherms, average Nusselt number at the hot wall and average fluid temperature in the cavity for the mentioned parameters. The results showed that the flow and thermal fields through streamlines and isotherms as well as the rate of heat transfer from the heated wall in terms of Nusselt number are strongly dependent on the length and locations of the heater as well as heat generating parameter.