接觸熱導
Multi tool use
接觸熱導（thermal contact conductance）是指二個固體在有熱接觸時的热传导。接觸熱導係數（thermal contact conductance coefficient）hc{displaystyle h_{c}}
是有二個相接觸的固體之間的熱導率，也表示其導熱的能力。接觸熱導係數的倒數稱為接觸熱阻（thermal contact resistance）。
定義
當二個固體相接觸（例如圖1的A和B），熱會由較高溫的物體流到較低溫的物體。二個固體的溫度分佈大致如圖1所示。在接觸面上有明顯的溫度落差，這就是二個接觸面之間接觸熱阻造成的影響。接觸熱阻定義為溫度差和介面平均熱流的比例[1]。
依照傅立葉定律，兩物體之間的熱流如下式所示：
q=−kAdTdx{displaystyle q=-kA{frac {dT}{dx}}}
|
|
(1)
|
其中q{displaystyle q}
為熱流，k{displaystyle k}
為熱傳導率，A{displaystyle A}
為截面積，dT/dx{displaystyle dT/dx}
是延著熱流方向的溫度梯度。
考慮能量守恆，兩物體之間的熱流可以用以下方式計算：
q=T1−T3ΔxA/(kAA)+1/(hcA)+ΔxB/(kBA){displaystyle q={frac {T_{1}-T_{3}}{Delta x_{A}/(k_{A}A)+1/(h_{c}A)+Delta x_{B}/(k_{B}A)}}}
|
|
(2)
|
可以看出熱流和兩物體的熱傳導率kA{displaystyle k_{A}}
和kB{displaystyle k_{B}}
，接觸面積A{displaystyle A}，以及接觸熱阻1/hc{displaystyle 1/h_{c}}
有關。而接觸熱阻的倒數即為接觸熱導係數hc{displaystyle h_{c}}。
參考資料
^ Holman, J. P. Heat Transfer, 8th Edition. McGraw-Hill. 1997.
Wb egU,9ESwzj6f2paAhIX6YVOsIz,8susn4x0MFPc,F
Popular posts from this blog
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ height:90px;width:728px;box-sizing:border-box;
}
1
I have 4 tables namely stud, country_master_academic,master_state and master_city. The main problem is that my form consists of many different fields like textbox, radio buttons, dropdown and an image file, so i am getting really confused. I can't insert data in database. Please help me. I tried many times but its not working. Thanks for the help in advance. Modal in home.php page <div class="container"> <div class="modal fade" id="add_data_modal" role="dialog"> <div class="modal-dialog"> <div class="modal-content"> ...
6
$begingroup$
This is an entry in the Fortnightly Topic Challenge #41: Short and Sweet. 1 letter only could be mean anything . With an additional letter in front , could be used as medicine component and something you definitely learn or at least heard once. Add another letter in front , you would possibly hear that many times . Add an additional letter in front , you would found an independent country . With an additional letter, in the end , you would found something related to apple . Add another letter in the end , you would found something bad . Hint: Each letter is unique .
word knowledge letters chemistry
share | improve this question
...
0
I am trying to run a scheduled task with User Group (not a single user). This is working fine when I in the field "when running a task, use the following user account:" insert BUILTIN User Group (for example: Administrators or Users). But when I try it with the created Local User Group (example: TestGroup) it is not working. The Users in the TestGroup are the same as in the Administrators group. What could be the problem? Are there some restrictions to the Created User Group compared to BUILTINUsers?
scheduled-tasks taskscheduler windowstaskschedule
share | improve this question
asked Nov 15 '18 at 15:36
Far...
这是与熱力學相关的小作品。你可以通过编辑或修订扩充其内容。
