射流水冷结构对离心泵性能影响的试验研究

与风冷系统对离心泵电动机进行散热相比,采用水冷系统能降低离心泵机组运行过程中电动机的噪声.为模拟水冷电动机冷却水的循环过程,设计了一种引射流装置,测试了去除电动机风扇前后离心泵机组在不同流量下噪声变化情况,研究了引射管径分别为6 mm和10 mm情况下离心泵的能量性能及空化特性.结果表明:相比较于风冷电动机,去除电动机风扇后泵机组随流量变化的系统噪声至少降低8.70 dB;引射管径为6 mm时能满足电动机的散热需要,对泵的性能和空化特性影响不大,并且在小流量工况下有改善泵驼峰的趋势;引射管径为10 mm时,泵的能量性能和空化特性变化较大,且在大流量工况下下降明显,这主要是由于引射管径太大,加大了泵的泄漏量,增加了其容积损失;引射管径为10 mm时,流量在0~15 m³/h范围内,泵扬程略有上升,关死点扬程提高了0.30 m.

Experiments on effects of AC motor water-cooling device on performance of centrifugal pump

The noise of AC motor cooling fan may be decreased effectively by employing a water-coo-ling system compared with a usual air-cooling system. In this paper a kind of water-cooling device is designed to simulate the cooling water circulation process in an AC motor. The noise levels of the centrifugal pump with cooling fan and with water-cooling device are measured at various flow rates, respectively. Furthermore, the pump hydraulic and suction performances are tested for the devices with 6 mm and 10 mm diameter discharge nozzles and compared with the corresponding performances of the original pump. It is shown that the noise level of the original pump is reduced at least by 8.70 dB. The device with 6 mm diameter discharge nozzle can take away the heat generated by the AC motor and is subject to a little influence upon the hydraulic and suction performances. Interestingly, that device can raise the pump head at a low flow rate. Even though the device with 10 mm diameter discharge nozzle can improve the head over the 0-15 m³/h flow rate range, particularly the head is increased by 0.30 m at the shut-off condition, unfortunately, both the hydraulic and suction performances are degraded notably by the device, especially at a high flow rate. The increased leakage or volumetric loss in the pump caused from the enlarged nozzle diameter is responsible for the performance degradation.