This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined d...This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined directly on an aluminum plate(180 mm×120 mm×3 mm) covered by a transparent plate.The working fluid employed is ethanol.As a result,various flow patterns and their transitions are observed and found to be related to the fluid fill ratio,input heat load and the device orientation.Also the operational characteristics and working mechanism are discussed.展开更多
This paper presents an experimental study on a flat plate closed loop pulsating heat pipes. It consisted of total 40 channels with square cross section （2 × 2 mm^2, 165 mm long） machined directly on an aluminum...This paper presents an experimental study on a flat plate closed loop pulsating heat pipes. It consisted of total 40 channels with square cross section （2 × 2 mm^2, 165 mm long） machined directly on an aluminum plate（180×120×3 nm^2）, which was covered by a transparent plate. The working fluid employed was ethanol. As the results, the influence parameters of thermal performance were investigated, such as filling ratio, heat load and operational orientations etc. Filling ratio was found to be a critical parameter, and its effect was rather complicated. According to its values the PHP plate could have four distinct working zones with different operational characteristics and heat transfer performance. The effect of heat load on thermal performance was found to be positive, and in general, iucrcasing the heat load would improve heat transfer performance. In order to analyze the effect of gravity on thermal performance, three different heat modes and total seven tilt angles were tested and compared. Successful operation at all orientations with respect to gravity was also achieved.展开更多
Using ethanol or acetone as the working fluid, the performance of starting up and heat transfer of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying fi...Using ethanol or acetone as the working fluid, the performance of starting up and heat transfer of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying filling ratio, inclination, working fluids and heating power. The performance of the tested pulsating heat pipe was mainly evaluated by thermal resistance and wall temperature. Heating copper block and cold water bath were adopted in the experimental investigations. It was found that oscillating heat pipe with filling ratio of 50% started up earlier than that with 70% when heating input was 159.4 W, however, it has similar starting up performance with filling ratio of 50% as compared to 70% on the condition of heat input of 205.4 W. And heat pipe with filling ratio of 10% could not start up but directly transit to dry burning. A reasonable filling ratio range of 35%-70% was needed in order to achieve better performance, and there are different optimal filling ratios with different heating inputs- the more heating input, the higher optimal filling ratio, and vice versa. However, the dry burning appeared easily with low filling ratio, especially at very low filling ratio, such as 10%. And higher filling ratio, such as 70%, resulted in higher heat transfer( dry burning) limit. With filling ratio of 70% and inclination of 75°, oscillating heat pipe with acetone started up with heating input of just 24 W, but for ethanol, it needed to be achieved 68 W, Furthermore, the start time with acetone was similar as compared to that with ethanol. For steady operating state, the heating input with acetone was about 80 W, but it transited to dry burning state when heating input was greater than 160 W. However, for ethanol, the heating input was in vicinity of 160 W. Furthermore, thermal resistance with acetone was lower than that with ethanol at the same heating input of 120 W.展开更多
We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used a...We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used as an H-field reflector to direct more H-field to each resonator, and the L-matching network is employed to match the 50 Ω of the feed cable at 13.56 MHz. Two identical resonators with dimensions of 30 cm × 15 cm are separated by 50 cm, and the resulting transmission efficiency is about ?12.3 dB at 13.56 MHz. This is about 4.2 dB higher than the resonators without the ferrite plate.展开更多
[目的]探讨依据术前CT预备钩钢板治疗肩锁关节脱位的临床疗效。[方法]回顾性分析2020年1月-2022年12月本院收治的60例急性闭合肩锁关节脱位患者的临床资料。根据医患沟通结果,30例采用预备钩钢板治疗(钩板组),30例采用袢钢板重建喙锁韧...[目的]探讨依据术前CT预备钩钢板治疗肩锁关节脱位的临床疗效。[方法]回顾性分析2020年1月-2022年12月本院收治的60例急性闭合肩锁关节脱位患者的临床资料。根据医患沟通结果,30例采用预备钩钢板治疗(钩板组),30例采用袢钢板重建喙锁韧带治疗(袢钢板组),比较两组临床及影像结果。[结果]钩板组手术时间[(40.5±8.7) min vs (61.9±11.4) min,P<0.001]、切口长度[(6.3±1.6) cm vs (7.50±2.2) cm, P<0.001]、术中出血量[(52.6±14.8) m L vs (75.4±13.2) m L, P<0.001]均显著少于袢钢板组。与术后3个月相比,末次随访时两组患者VAS、Constant评分及肩前屈上举活动度均无显著变化(P<0.05)。相应时间点,两组间VAS、Constant评分及肩前屈上举活动度的差异均无统计学意义(P>0.05)。影像方面,与术前相比,术后6个月两组肩锁间距(acromioclavicular distance, AC)、喙锁间距(coracoclavicular distance, CC)均显著减小(P<0.05),相应时间点,两组间AC、CC比较的差异均无统计学意义(P>0.05)。[结论]术前CT预备钩钢板治疗肩锁关节脱位操作简单,费用低廉,临床疗效满意。展开更多
基金the Ger man National Science Foundation (GR-412/33-2)Shanghai Leading Academic Discipline Project (No.B604)
文摘This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined directly on an aluminum plate(180 mm×120 mm×3 mm) covered by a transparent plate.The working fluid employed is ethanol.As a result,various flow patterns and their transitions are observed and found to be related to the fluid fill ratio,input heat load and the device orientation.Also the operational characteristics and working mechanism are discussed.
基金Supported by the Ger man National Science Foundation (DFG)(No. GR412/33)
文摘This paper presents an experimental study on a flat plate closed loop pulsating heat pipes. It consisted of total 40 channels with square cross section （2 × 2 mm^2, 165 mm long） machined directly on an aluminum plate（180×120×3 nm^2）, which was covered by a transparent plate. The working fluid employed was ethanol. As the results, the influence parameters of thermal performance were investigated, such as filling ratio, heat load and operational orientations etc. Filling ratio was found to be a critical parameter, and its effect was rather complicated. According to its values the PHP plate could have four distinct working zones with different operational characteristics and heat transfer performance. The effect of heat load on thermal performance was found to be positive, and in general, iucrcasing the heat load would improve heat transfer performance. In order to analyze the effect of gravity on thermal performance, three different heat modes and total seven tilt angles were tested and compared. Successful operation at all orientations with respect to gravity was also achieved.
基金Project 51306198 supported by National Natural Science Foundation of ChinaProject 00921915023 supported by Organization Department of Beijing+1 种基金Project NR2013K07 supported by Beijing Key Lab of Heating,Gas Supply,Ventilating and Air Conditioning EngineeringProject 331614013 supported by Beijing University of Civil Engineering and Architecture
文摘Using ethanol or acetone as the working fluid, the performance of starting up and heat transfer of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying filling ratio, inclination, working fluids and heating power. The performance of the tested pulsating heat pipe was mainly evaluated by thermal resistance and wall temperature. Heating copper block and cold water bath were adopted in the experimental investigations. It was found that oscillating heat pipe with filling ratio of 50% started up earlier than that with 70% when heating input was 159.4 W, however, it has similar starting up performance with filling ratio of 50% as compared to 70% on the condition of heat input of 205.4 W. And heat pipe with filling ratio of 10% could not start up but directly transit to dry burning. A reasonable filling ratio range of 35%-70% was needed in order to achieve better performance, and there are different optimal filling ratios with different heating inputs- the more heating input, the higher optimal filling ratio, and vice versa. However, the dry burning appeared easily with low filling ratio, especially at very low filling ratio, such as 10%. And higher filling ratio, such as 70%, resulted in higher heat transfer( dry burning) limit. With filling ratio of 70% and inclination of 75°, oscillating heat pipe with acetone started up with heating input of just 24 W, but for ethanol, it needed to be achieved 68 W, Furthermore, the start time with acetone was similar as compared to that with ethanol. For steady operating state, the heating input with acetone was about 80 W, but it transited to dry burning state when heating input was greater than 160 W. However, for ethanol, the heating input was in vicinity of 160 W. Furthermore, thermal resistance with acetone was lower than that with ethanol at the same heating input of 120 W.
文摘We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used as an H-field reflector to direct more H-field to each resonator, and the L-matching network is employed to match the 50 Ω of the feed cable at 13.56 MHz. Two identical resonators with dimensions of 30 cm × 15 cm are separated by 50 cm, and the resulting transmission efficiency is about ?12.3 dB at 13.56 MHz. This is about 4.2 dB higher than the resonators without the ferrite plate.
文摘[目的]探讨依据术前CT预备钩钢板治疗肩锁关节脱位的临床疗效。[方法]回顾性分析2020年1月-2022年12月本院收治的60例急性闭合肩锁关节脱位患者的临床资料。根据医患沟通结果,30例采用预备钩钢板治疗(钩板组),30例采用袢钢板重建喙锁韧带治疗(袢钢板组),比较两组临床及影像结果。[结果]钩板组手术时间[(40.5±8.7) min vs (61.9±11.4) min,P<0.001]、切口长度[(6.3±1.6) cm vs (7.50±2.2) cm, P<0.001]、术中出血量[(52.6±14.8) m L vs (75.4±13.2) m L, P<0.001]均显著少于袢钢板组。与术后3个月相比,末次随访时两组患者VAS、Constant评分及肩前屈上举活动度均无显著变化(P<0.05)。相应时间点,两组间VAS、Constant评分及肩前屈上举活动度的差异均无统计学意义(P>0.05)。影像方面,与术前相比,术后6个月两组肩锁间距(acromioclavicular distance, AC)、喙锁间距(coracoclavicular distance, CC)均显著减小(P<0.05),相应时间点,两组间AC、CC比较的差异均无统计学意义(P>0.05)。[结论]术前CT预备钩钢板治疗肩锁关节脱位操作简单,费用低廉,临床疗效满意。
