熱擴散率

在傳熱分析中，熱擴散率（符號： $\alpha \,$ ，但注意 $\kappa$ 、 $D$ 和 $k$ 都很常用）是熱導率與容積熱容之比。

\alpha ={k \over {\rho c_{p}}}

其中：

$k\,$ ：熱導率（單位：W/(m K)）
$\rho c_{p}\,$ ：容積熱容（單位：J/(m³K)）
$\rho \,$ ：密度（單位：kg/(m³)）
$c_{p}\,$ ：比熱容（單位：J/(kg K)）

熱擴散率的單位是m²/s。

對於普通的岩石來說， $\alpha \,$ ~ 10^-6 m²/s。在300K，空氣的熱擴散率是0.000024 m²/s。

對於空氣的熱擴散率與絕對溫度之間的關係，參見[1]。

部分材料與物質的熱擴散率

部分材料與物質的熱擴散率^[1]
材質	熱擴散率 (mm²/s)	來源
Pyrolytic graphite, parallel to layers	1220
碳/碳纖維 at 25 °C	216.5	^[2]
氦氣 (300 K, 1 atm)	190	^[3]
純銀 (99.9%)	165.63
氫氣 (300 K, 1 atm)	160	^[3]
金	127	^[4]
銅 at 25 °C	111	^[2]
鋁	97	^[4]
矽	88	^[4]
鋁-10矽-錳-鎂 (Silafont 36) at 20 °C	74.2	^[5]
6061-T6 鋁合金	64	^[4]
鉬 (99.95%) at 25 °C	54.3	^[6]
鋁-5鎂-2矽-錳 (Magsimal-59) at 20 °C	44.0	^[7]
錫	40	^[4]
水蒸氣 (1 atm, 400 K)	23.38
鐵	23	^[4]
氬氣 (300 K, 1 atm)	22	^[3]
氮氣 (300 K, 1 atm)	22	^[3]
空氣 (300 K)	19	^[4]
鋼, AISI 1010 (0.1% carbon)	18.8	^[8]
氧化鋁 (polycrystalline)	12.0
鋼, 1% carbon	11.72
Si₃N₄ with CNTs 26 °C	9.142	^[9]
Si₃N₄ without CNTs 26 °C	8.605	^[9]
304不鏽鋼 at 27 °C	4.2	^[4]
熱解石墨, normal to layers	3.6
310不鏽鋼 at 25 °C	3.352	^[10]
Inconel 600 at 25 °C	3.428	^[11]
石英	1.4	^[4]
砂岩	1.15
冰 at 0 °C	1.02
二氧化矽 (polycrystalline)	0.83	^[4]
磚塊, common	0.52
玻璃窗戶	0.34
磚塊, adobe	0.27
PC塑膠 (polycarbonate) at 25 °C	0.144	^[12]
水 at 25 °C	0.143	^[12]
PTFE塑膠 (Polytetrafluorethylene) at 25 °C	0.124	^[13]
PP塑膠 (polypropylene) at 25 °C	0.096	^[12]
尼龍	0.09
橡膠	0.089 - 0.13	^[14]
木材 (黃松)	0.082
石蠟 at 25 °C	0.081	^[12]
PVC塑膠 (polyvinyl chloride)	0.08	^[4]
引擎用油 (saturated liquid, 100 °C)	0.0738
酒精	0.07	^[4]

參見

^ Brown; Marco. Introduction to Heat Transfer 3rd. McGraw-Hill. 1958. and Eckert; Drake. Heat and Mass Transfer. McGraw-Hill. 1959. ISBN 978-0-89116-553-8. cited in Holman, J.P. Heat Transfer 9th. McGraw-Hill. 2002. ISBN 978-0-07-029639-8.
^ ^2.0 ^2.1 V. Casalegno; P. Vavassori; M. Valle; M. Ferraris; M. Salvo; G. Pintsuk. Measurement of thermal properties of a ceramic/metal joint by laser flash method. Journal of Nuclear Materials. 2010, 407 (2): 83. Bibcode:2010JNuM..407...83C. doi:10.1016/j.jnucmat.2010.09.032.
^ ^3.0 ^3.1 ^3.2 ^3.3 Lide, David R. (編). CDC Handbook of Chemistry and Physics 71st. Boston: Chemical Rubber Publishing Company. 1992. cited in Baierlein, Ralph. Thermal Physics. Cambridge, UK: Cambridge University Press. 1999: 372 [1 December 2011]. ISBN 978-0-521-59082-2.
^ ^4.00 ^4.01 ^4.02 ^4.03 ^4.04 ^4.05 ^4.06 ^4.07 ^4.08 ^4.09 ^4.10 ^4.11 Jim Wilson. Materials Data. August 2007 [2021-11-07]. （原始內容存檔於2021-11-08）.
^ P. Hofer; E. Kaschnitz. Thermal diffusivity of the aluminium alloy Al-10Si-Mn-Mg (Silafont 36) in the solid and liquid states. High Temperatures – High Pressures. 2011, 40 (3–4): 311 [2021-11-07]. （原始內容存檔於2016-03-04）.
^ A. Lindemann; J. Blumm. Measurement of the Thermophysical Properties of Pure Molybdenum. 17th Plansee Seminar 3. 2009.
^ E. Kaschnitz; M. Küblböck. Thermal diffusivity of the aluminium alloy Al-5Mg-2Si-Mn (Magsimal-59) in the solid and liquid states. High Temperatures – High Pressures. 2008, 37 (3): 221 [2021-11-07]. （原始內容存檔於2016-03-04）.
^ Lienhard, John H. Lienhard, John H. A Heat Transfer Textbook 5th. Dover Pub. 2019: 715.
^ ^9.0 ^9.1 O. Koszor; A. Lindemann; F. Davin; C. Balázsi. Observation of thermophysical and tribological properties of CNT reinforced Si₃ N₄. Key Engineering Materials. 2009, 409: 354. S2CID 136957396. doi:10.4028/www.scientific.net/KEM.409.354.
^ J. Blumm; A. Lindemann; B. Niedrig; R. Campbell. Measurement of Selected Thermophysical Properties of the NPL Certified Reference Material Stainless Steel 310. International Journal of Thermophysics. 2007, 28 (2): 674. Bibcode:2007IJT....28..674B. S2CID 120628607. doi:10.1007/s10765-007-0177-z.
^ J. Blumm; A. Lindemann; B. Niedrig. Measurement of the thermophysical properties of an NPL thermal conductivity standard Inconel 600. High Temperatures – High Pressures. 2003–2007, 35/36 (6): 621 [2021-11-07]. doi:10.1068/htjr145. （原始內容存檔於2015-09-24）.
^ ^12.0 ^12.1 ^12.2 ^12.3 J. Blumm; A. Lindemann. Characterization of the thermophysical properties of molten polymers and liquids using the flash technique. High Temperatures – High Pressures. 2003–2007, 35/36 (6): 627. doi:10.1068/htjr144.
^ J. Blumm; A. Lindemann; M. Meyer; C. Strasser. Characterization of PTFE Using Advanced Thermal Analysis Technique. International Journal of Thermophysics. 2011, 40 (3–4): 311. Bibcode:2010IJT....31.1919B. S2CID 122020437. doi:10.1007/s10765-008-0512-z.
^ 引用錯誤：沒有為名為AJP的參考文獻提供內容

[1] Brown; Marco. Introduction to Heat Transfer 3rd. McGraw-Hill. 1958. and Eckert; Drake. Heat and Mass Transfer. McGraw-Hill. 1959. ISBN 978-0-89116-553-8. cited in Holman, J.P. Heat Transfer 9th. McGraw-Hill. 2002. ISBN 978-0-07-029639-8.

[Casalegno2010-2] 2.0 ^2.1 V. Casalegno; P. Vavassori; M. Valle; M. Ferraris; M. Salvo; G. Pintsuk. Measurement of thermal properties of a ceramic/metal joint by laser flash method. Journal of Nuclear Materials. 2010, 407 (2): 83. Bibcode:2010JNuM..407...83C. doi:10.1016/j.jnucmat.2010.09.032.

[baierlein-3] 3.0 ^3.1 ^3.2 ^3.3 Lide, David R. (編). CDC Handbook of Chemistry and Physics 71st. Boston: Chemical Rubber Publishing Company. 1992. cited in Baierlein, Ralph. Thermal Physics. Cambridge, UK: Cambridge University Press. 1999: 372 [1 December 2011]. ISBN 978-0-521-59082-2.

[eleccool-4] 4.00 ^4.01 ^4.02 ^4.03 ^4.04 ^4.05 ^4.06 ^4.07 ^4.08 ^4.09 ^4.10 ^4.11 Jim Wilson. Materials Data. August 2007 [2021-11-07]. （原始內容存檔於2021-11-08）.

[5] P. Hofer; E. Kaschnitz. Thermal diffusivity of the aluminium alloy Al-10Si-Mn-Mg (Silafont 36) in the solid and liquid states. High Temperatures – High Pressures. 2011, 40 (3–4): 311 [2021-11-07]. （原始內容存檔於2016-03-04）.

[6] A. Lindemann; J. Blumm. Measurement of the Thermophysical Properties of Pure Molybdenum. 17th Plansee Seminar 3. 2009.

[7] E. Kaschnitz; M. Küblböck. Thermal diffusivity of the aluminium alloy Al-5Mg-2Si-Mn (Magsimal-59) in the solid and liquid states. High Temperatures – High Pressures. 2008, 37 (3): 221 [2021-11-07]. （原始內容存檔於2016-03-04）.

[8] Lienhard, John H. Lienhard, John H. A Heat Transfer Textbook 5th. Dover Pub. 2019: 715.

[Koszor2009-9] 9.0 ^9.1 O. Koszor; A. Lindemann; F. Davin; C. Balázsi. Observation of thermophysical and tribological properties of CNT reinforced Si₃ N₄. Key Engineering Materials. 2009, 409: 354. S2CID 136957396. doi:10.4028/www.scientific.net/KEM.409.354.

[10] J. Blumm; A. Lindemann; B. Niedrig; R. Campbell. Measurement of Selected Thermophysical Properties of the NPL Certified Reference Material Stainless Steel 310. International Journal of Thermophysics. 2007, 28 (2): 674. Bibcode:2007IJT....28..674B. S2CID 120628607. doi:10.1007/s10765-007-0177-z.

[11] J. Blumm; A. Lindemann; B. Niedrig. Measurement of the thermophysical properties of an NPL thermal conductivity standard Inconel 600. High Temperatures – High Pressures. 2003–2007, 35/36 (6): 621 [2021-11-07]. doi:10.1068/htjr145. （原始內容存檔於2015-09-24）.

[HTHP3536pp627-12] 12.0 ^12.1 ^12.2 ^12.3 J. Blumm; A. Lindemann. Characterization of the thermophysical properties of molten polymers and liquids using the flash technique. High Temperatures – High Pressures. 2003–2007, 35/36 (6): 627. doi:10.1068/htjr144.

[13] J. Blumm; A. Lindemann; M. Meyer; C. Strasser. Characterization of PTFE Using Advanced Thermal Analysis Technique. International Journal of Thermophysics. 2011, 40 (3–4): 311. Bibcode:2010IJT....31.1919B. S2CID 122020437. doi:10.1007/s10765-008-0512-z.

[AJP-14] 引用錯誤：沒有為名為AJP的參考文獻提供內容

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