Experimental investigation of single loop thermosyphons utilized in motorized spindle shaft cooling

• Published in: Applied thermal engineering 2018-04, Vol.134, p.229-237
• Main Authors: Li, Fajing, Gao, Jianmin, Shi, Xiaojun, Liang, Feng, Zhu, Ke
• Format: Article
• Language: English
• Subjects: Cooling; Cooling effects; Evaporation; Fluidized bed combustion; Heat transfer; Heat transfer performance; Heating; Loop thermosyphon; Motorized spindles; Quantum theory; Shaft cooling; Start-up characteristics; Thermal conductivity; Thermodynamics; Thermosyphons
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.11.141

•A shaft cooling structure is designed based on loop thermosyphons.•A single loop thermosyphon is studied during heating and cooling of the same tube.•The optimal liquid filling ratio is obtained under the special condition.•Cooling effects of the cooling structure are simulated on the motorized spindle. In this paper, a shaft cooling structure of a grinding motorized spindle was designed based on loop thermosyphons. The evaporation and condensation sections of the loop thermosyphons were located on the same tube due to the thermal conductivity of the shaft. The experimental studies on both heat transfer performance and start-up characteristics of a single loop thermosyphon were performed under the special condition. Then, the cooling effect on the shaft was simulated depending on the obtained experimental data. Results demonstrated that the optimal liquid filling rate of a loop thermosyphon ranged between 50 and 60% under the special condition. Furthermore, a critical value of heating power between 20 W and 40 W was found. When the heating power exceeded this value, the temperature of the evaporation section increased rapidly without any fluctuation. The violent fluctuation of temperature at the upper evaporation section could be utilized as an indicator for the heat transfer limit. Finally, according to the simulation, the maximum temperature of the motorized spindle was reduced by approximately 28% under the effect of the designed cooling structure.