Numerical investigation of natural convection heat transfer for toucan beak with different temperatures

doi:10.7523/j.ucas.2024.027

Abstract

Abstract:

This study investigates the heat transfer characteristics of the Toco Toucan’s beak， which is known for its unique structural features and strong heat exchange capabilities， using natural convection numerical simulations in environments of 30 ℃ and 15 ℃， respectively. Temperature contours at different positions along the length of the beak were extracted. It was observed that the heat transfer efficiency of the beak is higher in high-temperature environments， whereas in low-temperature environments， only a distinct temperature boundary layer near the skull is evident. Analysis revealed significant variations in the local Rayleigh number （Ra_x ） near the skull in low-temperature environments， while Ra_x in the anterior midsection of the beak remains relatively small， resulting in less pronounced convective heat exchange in this region. Streamline diagrams illustrate that in high-temperature environments， the entrainment effect at the tip of the beak alleviates the heat exchange deficiency caused by the small surface area， effectively utilizing every part of the beak’s dissipating surface. However， in low-temperature environments， the entrainment effect of the beak is concentrated near the skull， resulting in inevitable heat loss. By analyzing three dimensionless numbers， C_p， C_f， and Nu， it was found that C_p values in the Maxilla are negative in both environments， promoting the influx of cold air into the boundary layer and improving heat exchange efficiency by reducing temperature differentials caused by preheating effects. Particularly in low-temperature environments， C_p and C_f_{values in the anterior midsection of the beak are almost zero， while Nu stabilizes at a relatively small value， minimizing heat loss from the beak’s surface. The above research results quantitatively elucidated the heat exchange characteristics of bird beaks. Through further studies， it is hoped to provide reference for exploring the geographical distribution of toucans.}

Key words: Toucan, beak heat exchange, natural convection, biological heat transfer

CLC Number:

TK124

Xing HUANG, Jianchao MU, Jie LIU, Yanbin HAO. Numerical investigation of natural convection heat transfer for toucan beak with different temperatures[J]. Journal of University of Chinese Academy of Sciences, 2026, 43(1): 33-41.

Figures/Tables 8

Fig. 1 3D model of a beak

Fig. 2 Beak model diagram

Table 1 Validation of a single horizontal cylindrical natural convection model

Ra	$N u ¯$	$N u r e f ¯$ ^[15,21-22]	相对偏差/%
10³	3.14	3.11	0.96
10⁴	5.02	4.80	4.58
10⁵	8.33	8.54	2.46

Table 1 Validation of a single horizontal cylindrical natural convection model

Ra	$N u ¯$	$N u r e f ¯$ ^[15,21-22]	相对偏差/%
10³	3.14	3.11	0.96
10⁴	5.02	4.80	4.58
10⁵	8.33	8.54	2.46

Fig. 3 Front-face， side-sectional， and boundarylayer grid diagrams

Table 2 Grid and region independence validation

网格量	区域 (D×S×B)	最小网格尺寸/mm	$N u ¯$
3 678 190	7H×7.5C×2L	0.4	9.200
4 176 056	7H×7.5C×2L	0.2	9.196
4 772 984	9H×9C×2L	0.4	9.209

Table 2 Grid and region independence validation

网格量	区域 (D×S×B)	最小网格尺寸/mm	$N u ¯$
3 678 190	7H×7.5C×2L	0.4	9.200
4 176 056	7H×7.5C×2L	0.2	9.196
4 772 984	9H×9C×2L	0.4	9.209

Fig. 4 Isothermal contours of the beak

Fig.5 Streamline for the different environments

Fig.6 Three dimensionless coefficients

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