求教：為什么阻力型風(fēng)力機(jī)不適用于發(fā)電？

一只想飛的貓

兩個(gè)問題：
1/幾乎所有的有關(guān)風(fēng)力發(fā)電的書都說：“阻力型風(fēng)力機(jī)不適用于發(fā)電？”這是為什么？
# L* f( \5 H$ F% N6 b) ~: \# v6 E( G2/為什么書上說垂直軸風(fēng)力機(jī)的風(fēng)能利用率不如水平軸風(fēng)力機(jī)？垂直軸風(fēng)力機(jī)的風(fēng)能利用率怎么計(jì)算？
( B- y! }* M! G1 B8 Y求教啦，先謝謝啦。

過街蛤蟆

大蝦的閑情逸致令在下佩服，肯定不象我等為生計(jì)而奔波的家伙，
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! e9 h2 K  A0 Y% |. e! Z閣下的第一個(gè)問題，這是一個(gè)數(shù)學(xué)問題，從數(shù)學(xué)模型看，效率在15%，這是計(jì)算結(jié)果，實(shí)際要小一些，
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) a7 l3 ?- {7 q5 [% x5 [$ [第二個(gè)問題，你說的這個(gè)是依據(jù)水平軸的計(jì)算公式算的，它葉尖的比速小，算出的結(jié)果就小，現(xiàn)在垂直軸有自己的公式計(jì)算，同樣是垂直軸，衍生出一批派生系列，有些和水平軸的速度差不多，小也小不多，
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' A8 l" [( R8 G2 z- E9 V阿拉奔波生計(jì)，空氣動(dòng)力學(xué)的東西也忘的差不多了，大蝦有空看看新理論，現(xiàn)在的理論很多，尤其是垂直軸的，

一只想飛的貓

過街兄過譽(yù)了。幾十年得來的退休銀子是給喝粥的，要想吃肉還得再奔。到機(jī)械社區(qū)來，得過街兄教誨受益匪淺呀，先謝謝啦。

耀子

垂直軸的技術(shù)相對(duì)來說還不成熟

KCXD-七刀

Henry duPont of Lorax Energy Systems in Block Island, Rhode Island, dropped by electronically to  enlighten us on the matter of vertical versus horizontal axis wind turbines (VAWT versus HAWT).


Henry says the advantages of the VAWT configuration (like the Quietrevolution elsewhere in the Wind Power section ) are that the generator and gearbox can be housed on the ground, and even some distance away from that turbine; and that a VAWT is omnidirectional and requires no yaw mechanism.
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The disadvantages of typical VAWT systems are that they usually operate near the ground where there's not much wind; they produce wavy (sinusoidal) power pulses to drive mechanism; they don't start themselves in a breeze; and repair of the main bearing usually means having to take the whole machine apart. (The Quietrevolution appears to solve at least the first problem by being mount ed on a tower.) Most importantly, the VAWT is typically about 40% less efficient than the HAWT in energy production. According to Henry, you would need a VAWT almost twice the size of a HAWT to get the same amount of juice.

& z. [  ~. }& k) I7 {0 l+ TThe main advantage of the HAWT is the increased efficiency in power production, and the smooth transfer of that power from the rotor to the gearbox. HAWTs are also generally mounted on taller towers, where they have exposure to higher wind velocities and present smaller footprints on the ground. However, they require tall cranes for set-up; they require a yaw system; and any maintenance required has to be done at the top of a tower. The photo here shows Henry duPont's colleague Kim Granbery at altitude during the installation of a new HAWT above the Western desert.

KCXD-七刀

Henry duPont of Lorax Energy Systems in Block Island, Rhode Island, dropped by electronically to  enlighten us on the matter of vertical versus horizontal axis wind turbines (VAWT versus HAWT).


Henry says the advantages of the VAWT configuration (like the Quietrevolution elsewhere in the Wind Power section ) are that the generator and gearbox can be housed on the ground, and even some distance away from that turbine; and that a VAWT is omnidirectional and requires no yaw mechanism. 垂直軸的好處：發(fā)電機(jī)和變速箱可以放在地上， 震動(dòng)噪音會(huì)被吸收。也不需要偏航裝置。
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The disadvantages of typical VAWT systems are that they usually operate near the ground where there's not much wind; they produce wavy (sinusoidal) power pulses to drive mechanism; they don't start themselves in a breeze; and repair of the main bearing usually means having to take the whole machine apart. (The Quietrevolution appears to solve at least the first problem by being mount ed on a tower.) Most importantly, the VAWT is typically about 40% less efficient than the HAWT in energy production. According to Henry, you would need a VAWT almost twice the size of a HAWT to get the same amount of juice. 垂直軸缺點(diǎn)： 從結(jié)構(gòu)上講， 垂直軸離地面更近， 風(fēng)量小， 轉(zhuǎn)化為能量也小。

7 {0 {" X6 B0 W7 GThe main advantage of the HAWT is the increased efficiency in power production, and the smooth transfer of that power from the rotor to the gearbox. HAWTs are also generally mounted on taller towers, where they have exposure to higher wind velocities and present smaller footprints on the ground. However, they require tall cranes for set-up; they require a yaw system; and any maintenance required has to be done at the top of a tower. The photo here shows Henry duPont's colleague Kim Granbery at altitude during the installation of a new HAWT above the Western desert. 水平軸的最大優(yōu)勢(shì)就是效率高， 主要原因是不需要很多的材料就可以得到很大的掃風(fēng)面積， 通常也足夠高度， 獲得更多的風(fēng)能。  而同樣多的材料在更接近地面的區(qū)域獲得風(fēng)能會(huì)少很多。水平軸的缺點(diǎn)是安裝要求高， 維修難度大， 活動(dòng)零部件多也會(huì)造成更高程度的磨損。

* P4 Z6 O# s7 L3 D- m1 o從效率上看， 獲得更多風(fēng)能， 需要單位成本內(nèi)的最大掃風(fēng)面積。假設(shè)3米長(zhǎng)的3個(gè)葉片可以獲得進(jìn)30平方米的掃風(fēng)面積， 而同樣3個(gè)3米的葉片， 作為垂直軸掃風(fēng)面積只是一個(gè)3米*零點(diǎn)幾米的長(zhǎng)方形面積， 而且還是近地面。
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關(guān)于阻力型和升力型垂直軸：
http://www.mfginamerica.com/wind-sail-type-vertical-axis-wind-turbines-111011.aspx
* h; r4 T! P, q8 i' W關(guān)鍵詞： 阻力型的葉輪轉(zhuǎn)速總是比風(fēng)速要低， 而升力型的垂直軸葉輪轉(zhuǎn)速總是比風(fēng)速快。 所以， 阻力型的垂直軸風(fēng)機(jī)效率不到升力型垂直軸的一半。 但阻力型的特點(diǎn)是更皮實(shí)耐用。

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