Natural convection heat transfer from a vertical column of finite number of heated circular cylinders immersed in molten solar salt

Razzaghpanah, Zahra; Sarunac, Nenad

doi:10.1016/j.ijheatmasstransfer.2019.01.070

Cited by 12 publications

(8 citation statements)

References 29 publications

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“…The average Nu for the first cylinder in a column is the same as for the single cylinder. The relative error of the other presented tubes for the ratio Nu iav /Nu 0av , compared with Razzaghpanah and Sarunac [19], is up to 5.2%. Figure 6b compares the presented average Nusselt numbers of the i th cylinder with Equation (22) of the authors Razzaghpanah and Sarunac [19] and Equations (11)-(13) of the authors Kitamura et al [15].…”

Section: Results Of the Tube Array 4 × 1amentioning

confidence: 75%

“…The relative error of the other presented tubes for the ratio Nu iav /Nu 0av , compared with Razzaghpanah and Sarunac [19], is up to 5.2%. Figure 6b compares the presented average Nusselt numbers of the i th cylinder with Equation (22) of the authors Razzaghpanah and Sarunac [19] and Equations (11)-(13) of the authors Kitamura et al [15]. The ratio of the average Nusselt number for the i th cylinder and single cylinder / for a vertical column of four horizontal cylinders at Ra = 10 4 is shown in Figure 6a.…”

Section: Results Of the Tube Array 4 × 1amentioning

confidence: 75%

Section: Results Of the Tube Array 4 × 1amentioning

confidence: 80%

“…As it is shown in Figure 5 The ratio of the average Nusselt number for the i th cylinder and single cylinder / for a vertical column of four horizontal cylinders at Ra = 10 4 is shown in Figure 6a. The presented values were compared with Razzaghpanah and Sarunac [19] on the basis of Table 3 and Figure 9 [19] and Corcione [8] on the basis of Equation 17 [8]. The average Nu for the first cylinder in a column is the same as for the single cylinder.…”

Section: Results Of the Tube Array 4 × 1amentioning

confidence: 99%

“…The average Nu for the first cylinder in a column is the same as for the single cylinder. The relative error of the other presented tubes for the ratio / , compared with Razzaghpanah and Sarunac[19], is up to 5.2%.Figure 6bcompares the presented average Nusselt numbers of the i th cylinder with Equation (22) of the authors Razzaghpanah and Sarunac[19] and Equations (11)-(13) of the authors Kitamura et al[15]. Variation of the (a) ratio / vs. cylinder number; (b) average Nusselt number of the i th cylinder.Corcione[8] obtained numerical results for the average Nusselt number of the tube array Nuarray which may be correlated to the Rayleigh number Ra, the tube ratio spacing SV/D, and the number of the tubes in the array N: − log ( ),…”

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confidence: 96%

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Numerical Study of Heated Tube Arrays in the Laminar Free Convection Heat Transfer

Brodnianská

Kotšmíd

2020

Energies

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Laminar free convection heat transfer from a heated cylinder and tube arrays is studied numerically to obtain the local and average Nusselt numbers. To verify the numerical simulations, the Nusselt numbers for a single cylinder were compared to other authors for the Rayleigh numbers of 103 and 104. Furthermore, the vertically arranged heated tube arrays 4 × 1 and 4 × 2 with the tube ratio spacing SV/D = 2 were considered, and obtained average Nusselt numbers were compared to the existing correlating equations. A good agreement of the average Nusselt numbers for the single cylinder and the bottom tube of the 4 × 1 tube array is proved. On the other hand, the bottom tubes of the 4 × 2 tube array affect each other, and the Nusselt numbers have a different course compared to the single cylinder. The temperature fields for the tube array 4 × 4 in basic, concave, and convex configurations are studied, and new correlating equations were determined. The simulations were done for the Rayleigh numbers in the range of 1.3 × 104 to 3.7 × 104 with a tube ratio spacing S/D of 2, 2.5, and 3. On the basis of the results, the average Nusselt numbers increase with the Rayleigh numbers and tube spacing increasing. The average Nusselt number and total heat flux density for the convex configuration increase compared to the base one; on the other hand, the average Nusselt number decreases for the concave one. The results are applicable to the tube heaters constructional design in order to heat the ambient air effectively.

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Section: Results Of the Tube Array 4 × 1amentioning

confidence: 75%