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1
Content available PIV measurement of tube-side in a shell and tube heat exchanger
Wang K., Zhang Z., Liu Q., Tu X., Hyoung-Bum K.
Polish Journal of Chemical Technology
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2018
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Vol. 20, nr 1
60--66
EN
In order to improve the performance of the shell and tube heat exchanger, a porous baffle and a splitter bar are employed in this research. Through the arrangement of the porous baffle in the tube-side inlet and the splitter bar in the tube, the flow distribution of liquid in the heat exchanger is improved. PIV technology is used to investigate the unsteady flow in the tube-side inlet and the outlet of different models. The porous baffle significantly improves the flow of fluid in the shell and tube heat exchanger, especially by eliminating/minimizing the maldistribution of fluid flow in the tube-side inlet. The performance of the arc baffle is better than that of the straight baffle. The splitter bar has a minimal effect on the flow field of the tube-side inlet, but it effectively improves the flow in the tube bundle and restrains the vortex generation in the tube-side outlet.
2
Content available remote Analysis of Monitoring and Numerical Simulation on Anchor Force of Foundation Pit
Wang G., Zhang Q., Huang X., Tu X.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 3b
216--220
EN
Pile anchor supporting structure is a common method in deep foundation pit engineering. To a certain extent, anchor forces can reflect the earth pressure acting on the supporting structures. In the process of the deep foundation pit construction, the layers with different types of groundwater are often encountered. Improper control of groundwater may lead to engineering safety problems and many other cases which can cause bad effects on the surrounding environment. Therefore, it is of practical significance to conduct the optimal designs for supporting structures of deep foundation pit by monitoring the anchor forces in-situ. Through studying and analyzing the monitoring data, the earth pressure’s magnitude and distribution law can be further understood. In this paper, foundation pit engineering is taken as a base, a whole monitoring of the actual anchor forces is made in the process of tensioning, locking and working of anchors, and the monitoring data is analyzed. A numerical analysis based on the fluid-solid coupling theory of unsaturated soil is performed, and tests of the soil water characteristic curve (SWCC) for typical unsaturated soil are carried out. Finally, the test results are applied to numerical analysis. The results of anchor forces calculated by considering the coupled condition and ignoring the groundwater’s effect are compared with the monitoring results of engineering site. The comparison indicates that numerical results are inconsistent with measured results. The numerical results are close to the measured results only when the fluid-solid coupling theory of unsaturated soil is considered.
PL
W artykule przedstawiono wyniki badań dotyczących budowy głębokich fundamentów oraz ich utrzymania, w odniesieniu do ich odporności na pojawiające się czynniki (siły) zewnętrzne. Analizie poddano dane dotyczące sił kotwiczących fundamentów, zapewniających stabilność budowli, a w szczególności tzw. roztwór glebowy. Otrzymane wyniki zostały porównane z wynikami badań nie uwzględniającymi roztworu glebowego oraz wielkościami pomierzonymi. W ten sposób wykazano duży wpływ tego czynnika na wyniki analiz.
3
Content available remote An Integrated Vessel Tracking System by Using AIS, Inmarsat and China Beidou Navigation Satellite System
Yang C., Hu Q., Tu X., Geng J.
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
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2012
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Vol. 6, no. 2
175--178
EN
As there are more and more Automatic Identification System (AIS) sets have been deployed onboard, it is getting easier for people to trace vessels. Today, many online vessel monitoring services have been developed; however, most of them are based on AIS information. Because the coverage limitation of VHF frequency, which the AIS set works on, is normally no more than 25 nautical miles, so these systems can not track vessels when they are beyond the coverage of the shore-based AIS station. In order to track ves-sels in all sea areas, we developed a comprehensive vessel tracking system, namely ManyShips, which inte-grates AIS, Inmarsat and China Beidou navigation satellite system. The running result of the system shows that the Beidou satellite system can track vessels within Asian-Pacific region while the Inmarsat-C station polling service can help people tracking vessels within sea area A3.
4
Content available remote Maximum Torque per Ampere Control of Novel Transverse Flux Permanent Magnet Motor with Brushless DC Drive
Tu X., Gu C.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 4a
285-288
EN
A novel transverse-flux permanent magnet motor (TFPMM) with relatively simpler structure and BLDC drive is well suited for direct-drive electric vehicle. The commutation process in 120°-elec.-conduction is analyzed. To obtain maximum torque per ampere in open-loop application, a cost-effective approach based on phase advance commutation is proposed. Under varying load torque conditions, the required phase advance angle is automatically determined by both DC bus current and rotor speed. Both simulations and experiments are presented to verify its validity.
PL
Zaprezentowano nową odmianę silnika bezszczotkowego DC z poprzecznym strumieniem wytwarzanym przez magnesy trwałe w zastosowaniu do pojazdów elektrycznych. Do otrzymania maksymalnego momentu opracowano optymalny system komutacji. Przy zmieniającym się obciążeniu wymagana faza wyprzedzenia kątowego jest określana automatycznie na podstawie prądu szyny i prędkości wirowania.
5
Content available remote Analysis of jacking force for rectangular pipe-jacking machine
Li H., Yang Y., Tu X., Wang T.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 9b
200-203
EN
For the electrical control system of push pipe driving machine, the adjustment of jacking force is critical to balancing the resistance force and moving the pipe string forward. This force should be well under control so as to avoid both the collapse (active failure) and the blow-out (passive failure) of the soil mass near the tunnel face. The aim of this paper is to determine the collapse and blow-out face jacking force of a rectangular tunnel. The analysis is carried out in the framework of the kinematic method of limit analysis theory. The numerical results obtained are presented and analyzed.
PL
W maszynach do przeciskania rur istotną role odgrywa siła przecisku (jacking force). W artykule analizuje się tę siłę dla prostokątnego tunelu.
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