AF泡沫泵在使用過程中能不能發(fā)生汽蝕

汽蝕磨損
  液體中球形汽蝕空泡的破壞不是瞬時產(chǎn)生的，而是經(jīng)過多次衰變過程。在這個過程中，液體以很高的速度中向空泡中心，其大部分動能在形成新空泡的瞬時轉(zhuǎn)變?yōu)橄蚋鱾€方向傳播的球形沖擊波。作用在繞流結(jié)構(gòu)元件壁面上沖擊波的機械作用力是汽蝕磨損的主要原因。
  對于水力機械汽蝕破壞進行大量試驗和觀測，可以假定磨損量w與液流相對速度V的冪律關(guān)系
 2.磨料磨損
除了上述的磨損外，AF泡沫泵過流部件的磨損都屬于磨料磨損。根據(jù)磨損特性，離心泵所有泵件可以分成兩大類，第一類包括葉輪和壓水室，其流道磨損最嚴(yán)重;第二類是懸浮液流從高壓腔向低壓腔回流時使其受到磨損的零件:泵體，葉輪外蓋板，密封件和軸封。
  從最快磨損件開始，磨損順序為:①泵體隔舌;②葉片入口邊;③葉輪密封環(huán);4軸封;⑤吸入側(cè)泵腔;⑥泵體擴散管。
3.磨損機理
 磨損機理如圖1 -3-4所示，由固體顆粒從不同角度對材料表面撞擊、顆粒旋轉(zhuǎn)(向前旋轉(zhuǎn)、向后旋轉(zhuǎn))、塑性變性、疲勞破壞等因素引起材料裸露表面的剝落。對磨蝕表面的微觀分析表明了這種機理，這取決于流動狀態(tài)。

Can AF foam pump cavitation occur during its use?

Cavitation wear

The failure of spherical cavitation in liquid is not instantaneous, but through multiple decay processes. In this process, the liquid moves to the center of the cavity at a very high speed, and most of its kinetic energy is transformed into a spherical shock wave propagating in all directions at the moment when a new bubble is formed. The main cause of cavitation wear is the mechanical force of shock wave acting on the wall of flow-around structural elements.

The power law relationship between the wear rate W and the relative velocity V of fluid flow can be assumed by a large number of experiments and observations on cavitation failure of hydraulic machinery.

2. Abrasive wear

In addition to the above wear, the wear of AF foam pump components is abrasive wear. According to the wear characteristics, all pump parts of centrifugal pump can be divided into two categories. The first category includes impeller and water chamber, whose runner wear is the most serious. The second category is the parts which are worn by suspension flow when it flows back from high pressure chamber to low pressure chamber: pump body, impeller outer cover plate, seal and shaft seal.

From the fastest wear parts, the order of wear is: 1) the tongue of the pump body; 2) the inlet side of the blade; 3) the impeller seal ring; 4 axle seals; 5) the suction side pump chamber; 5) the diffusion tube of the pump body.

3. Wear mechanism

The wear mechanism is shown in Fig. 1-3-4, which is caused by the impact of solid particles on the surface of materials from different angles, the rotation of particles (forward rotation, backward rotation), plastic deformation, fatigue damage and other factors. The microscopic analysis of the abrasive surface shows this mechanism, which depends on the flow state.