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  • How did we get from this to this ?

    我們怎麼會變成這樣?

  • In some ways the answer just boils down to  “climate change” - we need way more renewable  

    在某些方面,答案只是歸結為 "氣候變化"--我們需要更多的可再生能源。

  • energy, so it makes sense that lots and lots  of engineering and economic resources have  

    能源,所以,大量大量的工程和經濟資源都在情理之中。

  • gone into improving and enlarging windmills. But  whileclimate changecan explain why windmills  

    了改進和擴大風車。但是,雖然 "氣候變化 "可以解釋為什麼風車

  • have pushed towards really good design, it  doesn't explain what makes a design good.

    已經推動了真正的好設計,它並沒有解釋什麼是好設計。

  • I see three main features to explain: the sizethe number of blades, and the shape of the blades.

    我看主要有三個特點來解釋:葉片的大小、葉片的數量、葉片的形狀。

  • Size is easiest: the bigger the area , the more  wind you can use, and therefore the more wind  

    尺寸最簡單:面積越大,可以使用的風量越大,是以風量也越大。

  • energy you can capture . Plus, the higher up you  go, the less the wind itself is impeded by stuff  

    你可以捕捉到的能量 。另外,你越往上走,風本身受到的阻礙就越小。

  • on the ground, the faster it blows, and therefore  the more wind energy you can capture . So for a  

    地面上的風速越快,吹得越快,是以你能捕捉到的風能就越多。所以對於一個

  • windmill to have access to air with a lot  of energy , it should be giant and tall.

    風車要能接觸到空氣,獲得大量的能量,它應該是巨大而高大的。

  • However, a paradox of windmills is that they need  to capture energy from the wind while also letting  

    然而,風車的一個悖論是,它們需要從風中獲取能量,同時也讓

  • the wind past. If you extracted 100% of the  kinetic energy from the wind, it would stop moving  

    風過去。如果你從風中提取100%的動能,它就會停止移動。

  • and there'd be nowhere for incoming wind to goSo you have to let some wind through - calculation  

    這樣一來,進風就無處可去了。 所以你必須讓一些風通過--計算。

  • shows that a mathematically ideal windmill can  only extract 59% of the wind's kinetic energy .

    顯示,一個數學上理想的風車只能提取59%的風的動能 。

  • Since windmills can't block the wind  too much, they're faced with a tradeoff:  

    由於風車不能太過擋風,所以面臨著取捨。

  • either have fast-moving blades that cover a small  amount of area, or slow-moving blades that cover  

    要麼有快速移動的葉片,覆蓋少量的區域,要麼有緩慢移動的葉片,覆蓋

  • a large amount of area. This is because, just as  an airplane wing produces more lift the faster the  

    大面積。這是因為,就像飛機機翼產生更多的升力一樣,速度越快,升力越大。

  • plane is moving, a windmill bladecatchesmore  of the wind the faster it's moving - so roughly  

    飛機在移動,風車葉片在移動速度越快的情況下,就會 "捕捉 "到更多的風--是以,大致上來說

  • speaking, a fast-moving windmill, like modern  ones, needs correspondingly fewer, thinner blades  

    說起來,像現代的風車一樣,快速移動的風車需要相應的更少、更薄的葉片。

  • in order to not slow the wind too much, whileslow-moving windmill can have more, wider blades.

    以免風速太慢,而慢速的風車可以有更多、更寬的葉片。

  • Obviously, modern windmills have gone with  the narrow, fast approach. So why modern  

    很顯然,現代風車走的是窄而快的路子。那麼,為什麼現代

  • windmills are designed to spin more quickly than  old windmills - I mean, if slower were better,  

    風車的設計是為了比老式風車轉得更快--我是說,如果慢一點更好。

  • there would be no reason modern windmills  couldn't look like giant high-tech sails!

    現代的風車沒有理由不像巨大的高科技風帆!

  • The answer comes from Newton's third law: just as  the wind pushes the blades sideways to turn them,  

    答案來自牛頓第三定律:就像風把葉片推到側面去轉動一樣。

  • so the blades push back on the windgiving the air a reverse twist,  

    所以葉片對風的推力,使空氣產生反向扭曲。

  • and hence some rotational kinetic energywhich is energy the windmill doesn't capture.  

    從而獲得一些旋轉動能--這是風車沒有捕捉到的能量。

  • So the most efficient windmill will give  the wind the smallest twist possible.

    所以最有效的風車會給風以最小的扭轉。

  • And, you guessed it, the faster a windmill blade  moves, the less rotational energy it gives to the  

    而且,你猜對了,風車葉片移動的速度越快,它給風車的旋轉能量就越少。

  • wind. This might seem a little counter-intuitivebut a similar thing happens when a ball falls and  

    風。這似乎有點違反直覺,但類似的事情會發生,當一個球落下,並。

  • bounces off an angled block - if the block isn't  moving, conservation of momentum and energy mean  

    從有角度的木塊上反彈--如果木塊沒有移動,動量和能量的守恆意味著......。

  • that the ball bounces to the left and the block  gets pushed right. But if the block starts off  

    即球向左彈,擋板向右推。但如果球塊開始時

  • moving to the right, it's able to absorb more  of the ball's energy when it accelerates.  

    向右移動,它在加速時能夠吸收更多的球的能量。

  • The faster the block moves, the more energy  it extracts from the ball! (You can see this  

    球塊移動的速度越快,從球中提取的能量就越多!(你可以看到這一點。(你可以看到這個

  • because the ball moves less each time). Windmill  blades are a bit more complicated, but it's  

    因為球每次移動的次數較少)。)風車葉片比較複雜,但它的

  • roughly the same idea - for decent efficiency, a  windmill blade should be moving through the air at  

    大致相同的想法--為了達到適當的效率,風車葉片應該以以下速度在空氣中移動。

  • least five times faster than the incoming speed of  the windthough obviously different parts of the  

    至少是風速的五倍......雖然顯然是不同部位的風速。

  • windmill blade are moving at different speeds and  so the shape varies along the length of the blade.

    風車葉片以不同的速度運動,所以形狀沿著葉片的長度變化。

  • So in summary: an ideal power-generating  windmill is big to capture a lot of wind,  

    所以綜上所述:理想的發電風車是大的,可以捕捉大量的風。

  • tall to capture strong winds, fast-moving  to be most efficient, and narrow-bladed  

    高大才能抓住強風,快速移動才能效率最高,窄刃才是王道

  • because a fast-moving windmill (needs  to have a smaller blade area - aka,  

    因為快速移動的風車(需要有較小的葉片面積--也就是。

  • just a few, narrow blades) to  not slow down the wind too much.

    只是幾片,狹長的葉片),以免風速太慢。

  • This video was created in partnership  with Bill Gates, inspired by his new book  

    這段視頻是與比爾-蓋茨合作製作的,靈感來自於他的新書。

  • How to Avoid a Climate Disaster.” You can find  out more about how we can all work together to  

    "如何避免氣候災難"。你可以瞭解更多關於我們如何共同努力,以

  • avoid a climate disaster - like how we need  huge development in energy/grid storage in  

    避免氣候災難--就像我們需要在能源/電網儲存方面進行大規模開發一樣。

  • addition to renewable energy generationyou can find out more in the link below.

    除了可再生能源發電--你可以在下面的鏈接中瞭解更多。

How did we get from this to this ?

我們怎麼會變成這樣?

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B1 中級 中文 風車 葉片 能量 捕捉到 動能 速度

風車設計的物理學 (The Physics of Windmill Design)

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    Summer 發佈於 2021 年 03 月 02 日
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