An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper prese...An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper presents a numerical method for simulating the flow in practical commercial impellers. The predictions are compared with experimentally measured fan performance results. The predicted total pressure and efficiency for two fan models, whose optimum designs were determined by this method, agree well with the measured data for the design flow rate. The results show that the aerodynamic and noise levels for these two models are excellent. The paper also presents several new ideas about the shape of the front plate and the blade flow pattern to improve the flow in an impeller channel. The practical simulation methodology and results developed here will be very useful to the fan industry in the future.展开更多
respectively, where r = 1, 2, … , n, and il, i2, … , is are positive integers. In this paper, the Schur convexity of Fn（X, r） and Gn（x, r） are discussed. As applications, by a bijective transformation of indepen...respectively, where r = 1, 2, … , n, and il, i2, … , is are positive integers. In this paper, the Schur convexity of Fn（X, r） and Gn（x, r） are discussed. As applications, by a bijective transformation of independent variable for a Schur convex function, the authors obtain Schur convexity for some other symmetric functions, which subsumes the main results in recent literature; and by use of the theory of majorization establish some inequalities. In particular, the authors derive from the results of this paper the Weierstrass inequalities and the Ky Fan＇s inequality, and give a generalization of Safta＇s conjecture in the n-dimensional space and others.展开更多
文摘An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper presents a numerical method for simulating the flow in practical commercial impellers. The predictions are compared with experimentally measured fan performance results. The predicted total pressure and efficiency for two fan models, whose optimum designs were determined by this method, agree well with the measured data for the design flow rate. The results show that the aerodynamic and noise levels for these two models are excellent. The paper also presents several new ideas about the shape of the front plate and the blade flow pattern to improve the flow in an impeller channel. The practical simulation methodology and results developed here will be very useful to the fan industry in the future.
基金supported by the National Natural Science Foundation of China(Nos.11271118,10871061,11301172)the Nature Science Foundation of Hunan Province(No.12JJ3002)+1 种基金the Scientific Research Fund of Hunan Provincial Education Department(No.11A043)the Construct Program of the Key Discipline in Hunan Province
文摘respectively, where r = 1, 2, … , n, and il, i2, … , is are positive integers. In this paper, the Schur convexity of Fn（X, r） and Gn（x, r） are discussed. As applications, by a bijective transformation of independent variable for a Schur convex function, the authors obtain Schur convexity for some other symmetric functions, which subsumes the main results in recent literature; and by use of the theory of majorization establish some inequalities. In particular, the authors derive from the results of this paper the Weierstrass inequalities and the Ky Fan＇s inequality, and give a generalization of Safta＇s conjecture in the n-dimensional space and others.
