離心風機方面有著巨大的節能空間,可以獲得非?？捎^的社會和經濟效益。陜西風機?中離心通風機的損失類型主要有四種,分別為流動損失、容積損失、軸承摩擦損失和輪盤損失。后兩種有時統稱為機械損失,因為軸承摩擦損失是軸承旋轉摩擦產生的外部機械損失,輪蓋損失是由于葉輪旋轉時與周圍氣體摩擦產生的內部機械損失。

Centrifugal fan has huge energy-saving space and can obtain very considerable social and economic benefits. Shaanxi fan? There are four main loss types of centrifugal fan, namely flow loss, volume loss, bearing friction loss and disc loss. The latter two are sometimes collectively referred to as mechanical losses, because the bearing friction loss is the external mechanical loss caused by the bearing rotation friction, and the wheel cover loss is the internal mechanical loss caused by the friction between the impeller and the surrounding gas when the impeller rotates.

1、流動損失

1. Flow loss

陜西風機?主要的損失是流動損失,其根源在于氣體的黏性。流動損失可以分為邊界層摩擦損失和漩渦損失,后者包含邊界層分離、“射流尾跡”和二次流等引起的損失以及通風機在非額定工況下工作,由于氣流入口角與葉片入口角之間的差異引起的沖擊損失。流動損失與邊界層密切相關,一方面邊界層加厚會導致邊界內氣體摩擦損失加大,另一方面當邊界層發展到一定程度,靠近壁面的位置將出現倒流,導致邊界層脫離壁面而形成分離,從而形成一定渦區,引起較大損失。

Shaanxi fan? The main loss is the flow loss, which is rooted in the viscosity of the gas. The flow loss can be divided into boundary layer friction loss and vortex loss. The latter includes the loss caused by boundary layer separation, "jet wake" and secondary flow, as well as the impact loss caused by the difference between air inlet angle and blade inlet angle when the fan works under non rated working conditions. The flow loss is closely related to the boundary layer. On the one hand, the thickening of the boundary layer will increase the gas friction loss in the boundary. On the other hand, when the boundary layer develops to a certain extent, there will be backflow near the wall, resulting in the separation of the boundary layer from the wall, forming a fixed vortex area and causing great losses.

2、二次流損失

2. Secondary flow loss

在離心葉輪葉道內存在壓力梯度,在葉片表面和輪蓋輪盤表面邊界層內的流體形成的慣性力不能與葉道內的壓力梯度平衡,從而在邊界層內產生由壓力面流向吸力面的流動。該流動與葉道內的主流方向垂直,稱為二次流。二次流是輪蓋和輪盤表面邊界層內靠壓力面的低速流體微團被吸走,并使吸力面的邊界層變厚導致分離,引起損失。射流-尾跡現象的產生原因是吸力面上的邊界層分離影響到主流區的流動,在壓力面附近的形成擠壓區域,流速較高稱為射流。而在吸力面附近則相對速度較低,稱為尾跡。

There is a pressure gradient in the blade path of centrifugal impeller. The inertial force formed by the fluid in the boundary layer on the blade surface and the wheel cover disc surface cannot be balanced with the pressure gradient in the blade path, resulting in the flow from the pressure surface to the suction surface in the boundary layer. The flow is perpendicular to the main flow direction in the blade channel, which is called secondary flow. Secondary flow is that the low-speed fluid micro mass near the pressure surface in the boundary layer on the surface of wheel cover and wheel disc is sucked away, and the boundary layer on the suction surface becomes thicker, resulting in separation and loss. The reason for the jet wake phenomenon is that the boundary layer separation on the suction surface affects the flow in the mainstream area. A squeeze area is formed near the pressure surface, and the high velocity is called jet. The relative velocity near the suction surface is low, which is called wake.

集流器與葉輪入口之間存在一定的間隙,從葉輪流出的氣體有少部分會經過該間隙流回葉輪入口,這種由間隙引起的損失稱為容積損失。輪盤和輪蓋的摩擦損失會造成功率損失但是不降低壓力。另外,用于屋頂通風和風機墻的無蝸殼風機葉輪出口處的動能沒有轉化為靜壓,當氣流沖出葉輪后動能被全部損失掉,還存在動壓損失。

There is a certain gap between the collector and the impeller inlet, and a small part of the gas flowing out of the impeller will flow back to the impeller inlet through the gap. This loss caused by the gap is called volume loss. The friction loss between the wheel disc and the wheel cover will cause power loss, but does not reduce the pressure. In addition, the kinetic energy at the outlet of the volute free fan impeller for roof ventilation and fan wall is not converted into static pressure. When the air flow rushes out of the impeller, the kinetic energy is completely lost, and there is also dynamic pressure loss.

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This article is provided by Shaanxi centrifugal fan manufacturer. Our website is: http://www.makemoore.com We will serve you with wholehearted enthusiasm. Welcome to visit

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