求教：为什么阻力型风力机不适用于发电？

一只想飞的猫

两个问题：
! n! `; g" }0 n/ U* l/ D8 ^1/几乎所有的有关风力发电的书都说：“阻力型风力机不适用于发电？”这是为什么？
2/为什么书上说垂直轴风力机的风能利用率不如水平轴风力机？垂直轴风力机的风能利用率怎么计算？
& L  j+ o' c2 _4 p% J, t求教啦，先谢谢啦。

过街蛤蟆

大虾的闲情逸致令在下佩服，肯定不象我等为生计而奔波的家伙，

阁下的第一个问题，这是一个数学问题，从数学模型看，效率在15%，这是计算结果，实际要小一些，

第二个问题，你说的这个是依据水平轴的计算公式算的，它叶尖的比速小，算出的结果就小，现在垂直轴有自己的公式计算，同样是垂直轴，衍生出一批派生系列，有些和水平轴的速度差不多，小也小不多，
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4 z+ P/ e# P% f$ {阿拉奔波生计，空气动力学的东西也忘的差不多了，大虾有空看看新理论，现在的理论很多，尤其是垂直轴的，

一只想飞的猫

过街兄过誉了。几十年得来的退休银子是给喝粥的，要想吃肉还得再奔。到机械社区来，得过街兄教诲受益匪浅呀，先谢谢啦。

耀子

垂直轴的技术相对来说还不成熟

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).

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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.


9 D0 j1 l1 M! lThe 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.

, q  L( h! q9 rThe 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.
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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).
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: c& U* F5 p4 h; V! lHenry 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. 垂直轴的好处：发电机和变速箱可以放在地上， 震动噪音会被吸收。也不需要偏航装置。

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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. 垂直轴缺点： 从结构上讲， 垂直轴离地面更近， 风量小， 转化为能量也小。
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4 U* F2 C3 L8 L! V- p  @: mThe 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. 水平轴的最大优势就是效率高， 主要原因是不需要很多的材料就可以得到很大的扫风面积， 通常也足够高度， 获得更多的风能。  而同样多的材料在更接近地面的区域获得风能会少很多。水平轴的缺点是安装要求高， 维修难度大， 活动零部件多也会造成更高程度的磨损。

3 d+ y# @) C# [* u: Q2 w0 |从效率上看， 获得更多风能， 需要单位成本内的最大扫风面积。假设3米长的3个叶片可以获得进30平方米的扫风面积， 而同样3个3米的叶片， 作为垂直轴扫风面积只是一个3米*零点几米的长方形面积， 而且还是近地面。
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8 w1 S) Q! s; B- g# e9 t$ F$ h9 U关于阻力型和升力型垂直轴：
http://www.mfginamerica.com/wind-sail-type-vertical-axis-wind-turbines-111011.aspx
, t4 y: h" @* L) ?5 v/ E7 Y) Y关键词： 阻力型的叶轮转速总是比风速要低， 而升力型的垂直轴叶轮转速总是比风速快。 所以， 阻力型的垂直轴风机效率不到升力型垂直轴的一半。 但阻力型的特点是更皮实耐用。

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