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Finite Element Analysis and Experimental Study on the Thermal Resistance Characteristics of Motor Coolers

Xu Ke, Yang Jie, Tang Chuansheng, Zhao Qiang, Li Tao

Journal of Power Technologies

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2020

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Vol. 100, nr 3

279--289

EN

Motor coolers are operated with the coupling of temperature and pressure fields, in which the change rule is affected by multiple factors. In this study, the thermal resistance of the motorcooler was examined using the velocity coefficient method to reveal the influence of heat transfer and wind resistance. The temperature and pressure fields were analyzed using the finite element method based on the hydrodynamics and momentum theorem. By varying the heat transfer and wind resistance coefficients to reflect temperature and pressure characteristics, wind and water velocities were determined. Results demonstrate that the total convective heat transfer and wind resistance coefficients of the cooler model are sensitive to variations in face-to-face wind velocity, but not to those of the cooling water flow rate. When wind velocity increases from 0.8 to 5.19m/s, the total convective heat transfer increases by 1.85 times and wind resistance increases by 18.74 times. Variations in cooling water velocity has little effect on the Nusselt numberon the air side and the Euler number of the single row tube, which are multiplied with the increase of the Reynolds number. When the Reynolds number increases from 1020 to 6345, the Nusselt number increases by 2.05 times and the Euler numer decreases by 2.29 times. The results provide references for the design and performance testing of high-power motor coolers.

2

Research on product value of wheel diameter and rotational speed — A new design parameter for micro radial turbines

Fu L., Li G.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 2

231--239

EN

The physical realizability is the primarily consideration in micro radial turbine design. The determination of realizability mainly depends on the physical size (wheel diameter) and operation condition (rotational speed). In the past design, the product value of wheel diameter (D) and rotational speed (N) was taken as design result, but this value would lead repeating works because it may not appropriate for the realizability of micro radial turbine. This paper takes DN value as a design parameter to help the micro radial turbine design directly. The analysis of matching relationship between stage velocity ratio and degree of reaction was studied firstly. The influence of matching effects was investigated secondly. Then the DN value was presented and the theoretical research for optimal value selection was conducted thirdly. Compared with the other design parameters, the DN value can reflect the effect of efficiency, wheel size, rotational speed and design working condition directly and the effect of wheel material, structure style, shafting and bearings type directly. So the DN value is a highly concentrated and useful parameter for micro radial turbines. Some aerodynamic and structure parameters of micro radial turbine will be facilitated and designed by using the method of this paper.

3

Kompleksowa identyfikacja współczynnika prędkości osiadania dla warunków jednej z kopalń GZW

Ścigała R.

Górnictwo i Geologia

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2012

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T. 7, z. 1

199-210

PL

W artykule przedstawiono praktyczny przykład identyfikacji wartości współczynnika prędkości osiadania na podstawie wyników pomiarów geodezyjnych obniżeń według zaproponowanej przez autora metodyki [7], polegającej na jednoczesnym wyznaczaniu wartości tego parametru zarówno w przestrzeni współrzędnych geometrycznych, jak i współrzędnej czasowej. Prezentowany przykład oparto na wynikach pomiarów geodezyjnych z terenu jednej z kopalń GZW.

EN

The practical example of determination of subsidence rate coefficient on the basis of geodetic measurements results has been presented in this paper. The presented example bases on the Author's proposal of parameter "c" identification methodology by simultaneous best fit searching in the space and time coordinates. In identification procedure, the geodetic measurements results were used from one of Upper Silesia Basin coal mines.

4

Obliczanie współczynnika prędkości C dla koryt otwartych : artykuł przeglądowy

Mionczyńska N., Prystaj J.

Czasopismo Techniczne. Budownictwo

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1998

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R. 95, z. 5-B

55--63

EN

This paper is a monographical review of the most commonly used formulas for Chézy's velocity coefficient. Application range of each formula has been given.