转臂式高速离心机减阻设计及机室流场特性研究

Drag reduction and air flow field characteristics of high speed centrifuge chamber

摘要

风阻功率是大型转臂式土工离心机驱动功率设计的重要依据，机室流场具有随流、温升、流速高等特点。为降低风阻需对转臂或吊篮采取整流减阻设计。针对两型分别采用转臂整流和整流罩减阻的离心机，开展了基于CFD（computational fluid dynamics）的气动特性仿真，通过优化仿真参数获得离心机高速运行时的机室内部流场特性及离心机风阻功率，并通过型线设计对离心机整流罩进行了气动阻力系数优化。研究表明：高速离心机低气压运行时机室下壁面的摩擦阻力矩占主导，高于周向壁面的摩擦阻力矩；吊篮不采用整流罩时，在迎风端面肩部出现了流动分离，压差阻力较大；采用整流罩后，吊篮前缘肩部的分离被削弱，总阻力系数大幅降低。研究表明对于高速离心机开展整流设计是必要的，通过转臂外形设计及整流罩设计，可有效降低风阻功率，更有益于控制机室温升。

Abstract

The wind resistance power is an important basis for the design of the driving power of the large rotary arm geotechnical centrifuge. The flow field in the chamber has the characteristics of following flow, temperature rise, and high flow rate. In order to reduce the wind resistance, it is necessary to adopt rectification and drag reduction design for the swing arm or cradle. For the two types of centrifuges that adopt rotary arm rectification and fairing drag reduction, the aerodynamic characteristics simulation based on computational fluid dynamics (CFD) is carried out. The flow field characteristics of the internal flow field of the centrifuge chamber and the wind resistance power of the centrifuge are obtained by optimizing the simulation parameters, and the aerodynamic resistance coefficient of the centrifuge fairing is optimized through the profile design. The results show that when the high-speed centrifuge operates at low pressure, the friction resistance moment on the lower wall of the chamber is dominant, higher than that on the circumferential wall. When the basket does not use the fairing, the flow separation occurs at the shoulder of the windward end face, and the pressure difference resistance is large. After the fairing is adopted, the separation of the front edge shoulder of the basket is weakened, and the total drag coefficient is greatly reduced. The research shows that it is necessary to carry out rectification design for high-speed centrifuge. Through the shape design of the rotating arm and the design of the fairing, the wind resistance power can be effectively reduced, and it is more beneficial for controling the room temperature rise of the centrifuge.

关键词

转臂式离心机 / 高速转动 / 流场 / CFD / 整流罩

Key words

arm centrifuge / high velocity rotation / air flow field / CFD / fairing

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基金资助

十三五国家重大科研基础设施建设资助项目(CHIEF1500)