Study on calculation method of air resistance of high-speed monorail sled

2021 ◽  
Author(s):  
Xiao Jun ◽  
Zhang Wei-wei ◽  
Zhang Lin-rui ◽  
Wang Xiao-he ◽  
Geng Qiang ◽  
...  
2016 ◽  
Vol 693 ◽  
pp. 1585-1590
Author(s):  
Yi Zhuo Guo ◽  
Xian Guo Yan ◽  
Shu Juan Li ◽  
Hong Guo

Many studies have proved the service life of cutter can be prolonged by electrolytic strengthening. Based on the theory of electrolytic strengthening technology, this paper introduced and developed prototype equipment for strengthening cutting edge of rotary cutter and put forward a calculation method of total electric quantity consumption during the electrolysis suitable for microcontroller. The M8 high-speed steel tap is taken as a strengthening example. After finished the strengthening process that it clearly see the results of the surface of tap was obviously polished by observing the micrograph. This equipment improves the reliability of electrolytic strengthening and the cost is relatively cheap.


2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.


1933 ◽  
Vol 37 (271) ◽  
pp. 641-654
Author(s):  
J. Dick

The high-speed internal combustion engine presents many problems arising from dynamic effects. Amongst these is the phenomenon known as “ surging ” in the helical springs used for the operation of the valves.If a helical spring is held at both ends, any disturbance in the spring passes up and down as a wave, being reflected at each end in turn. This to and fro movement continues until it is damped out by friction and air resistance. With most springs the speed of propagation of the disturbance is considerable and only a confused flutter of the coils is apparent to an observer. A disturbance of this type is caused by any movement of the end of the spring. The more abrupt the movement of the end, the more pronounced will the disturbance be. An instance of the type of movement producing a pronounced surge is that due to impact between the tappet and the valve when the valve commences to open.


2019 ◽  
Vol 58 (7) ◽  
pp. 1037-1056 ◽  
Author(s):  
Yaohui Lu ◽  
Wei Bi ◽  
Xing Zhang ◽  
Jing Zeng ◽  
Tianli Chen ◽  
...  

2017 ◽  
Vol 44 (5) ◽  
pp. 0504007
Author(s):  
张玉燕 Zhang Yuyan ◽  
郭全丽 Guo Quanli ◽  
杨德功 Yang Degong ◽  
王振春 Wang Zhenchun

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4190 ◽  
Author(s):  
Eric Chaidez ◽  
Shankar P. Bhattacharyya ◽  
Adonios N. Karpetis

The Hyperloop system offers the promise of transportation over distances of 1000 km or more, at speeds approaching the speed of sound, without the complexity and cost of high-speed trains or commercial aviation. Two crucial technological issues must be addressed before a practical system can become operational: air resistance, and contact/levitation friction must both be minimized in order to minimize power requirements and system size. The present work addresses the second issue by estimating the power requirements for each of the three major modes of Hyperloop operation: rolling wheels, sliding air bearings, and levitating magnetic suspension systems. The salient features of each approach are examined using simple theories and a comparison is made of power consumption necessary in each case.


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