Experimental study of temperature distributions over the heat supply object surface located at a different height in a room with a working infrared heater

2021 ◽  
Author(s):  
Ivan V. Voloshko ◽  
Tatiana A. Nagornova ◽  
Vyacheslav I. Maksimov
2017 ◽  
Vol 69 (6) ◽  
pp. 1049-1065 ◽  
Author(s):  
Zhe Liu ◽  
Wei Chen ◽  
Desheng Li ◽  
Wenjing Zhang

Purpose In high-speed processing, the influence on the machining accuracy of a machine tool is greatly caused by the thermal deformation of the motorized spindle; a further study on the thermal characteristics of the spindle is given in this paper. This study aims to reduce the thermal error and improve the performance of the machine tool by discussing the relationships between the temperature distributions and rotating accuracy caused by the thermal deformations of the spindle. Design/methodology/approach The paper opted for a method combining the theoretical analysis and the experimental study to study the thermal stability of the high-speed motorized spindle. First of all, a finite element model of the spindle was built with ANSYS, whereby temperature distributions and the thermal deformations were successively obtained at different speeds. And then, both the temperature field and the rotating accuracy of the motorized spindle were measured simultaneously by the thermal stability experiment. Finally, the experimental and theoretical results were compared and validated. Findings The thermal stability of the motorized spindle was studied in this paper, and some findings from the study were as follows: the spindle’s rotating accuracy maintained good in X direction but bad in Y and Z directions in terms of the deformations; the higher front-end temperature of the spindle which can significantly affect the rotating accuracy is needed to be controlled mainly; the recovery speed of the spindle deformation lagged behind the temperature’s fallback speed; the vibration graph about radial rotating sensitivity synthesized by X1 and X2 presented a trifoliate shape. Originality/value Based on a built test-bed which can synchronously measure the motorized spindle’s temperature distribution and rotating accuracy with five-point method, the coupling effects of the thermal deformation and temperature are embodied, and not only the vibration graph but also the thermal tilt angles can be gained. Therefore, considering the influence of the thermal deformation on the heat generated by the bearings, the paper fulfilled a study by which it was obtained that the front-end temperature of the spindle, which was higher and could significantly affect the rotating accuracy, needed to be controlled mainly.


2018 ◽  
Vol 8 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Ilker Yilmaz ◽  
Harun Yilmaz ◽  
Omer Cam

Abstract In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.


Author(s):  
Yujing Sun ◽  
Jie Sun ◽  
Jianfeng Li

The objective of this study is to model the temperature distributions in milling analytically. In this article, previous research on heat generation and heat dissipation in the machining process was reviewed and then the temperature model in intermittent cutting with continuously varying chip thickness was established. The experimental study to measure cutting temperature in milling Ti6Al4V utilizing semi-artificial thermocouple was presented. The predicted and experimental results for milling process were presented and compared. The results showed that the proposed mathematical model could predict cutting temperature with high accuracy.


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