Experimental Research Of Liquid-Gas Phase Change Material In Temperature Auto-Adjusting Box-Girder Bridge

Based on the concrete box bridge structure as the main research object,Liquid-gas phase change materials is proposed in this paper by the automatic regulation of the cross section of interior and exterior temperature stress caused by the sunshine temperature difference,which is a kind of new technology to avoid temperature cracks appeared,That is the concrete pouring process,the encapsulated phase change liquid-gas phase change material from thermostat with pouring phase change storage or discharge energy thermal effect at a temperature range of liquid vapor phase change material,so smart regulation concrete structure internal temperature stress,prevent the formation of temperature cracks.The main contents include:(1)Based on the actual project-a main span of 160 meters Lao Tuanpo Yunnan No.1 Bridge’s structure field data at the highest temperature throughout the year,the strongest solar radiation conditions,analyzed the case structure sunshine temperature variation concrete bridge and draw on existing research results on this most unfavorable vertical temperature gradient temperature distribution of the bridge box structure were fitting,fitting the resulting temperature gradients in different load reduction after reduction factor loaded onto the MIDAS model,obtain bridge box structure under the most unfavorable temperature distribution safe use can withstand the maximum temperature difference,the temperature in order to analyze the housing needs of the bridge structure;(2)In terms of the phase transition from thermostat design principle,phase change materials,packaging materials and packaging container diameter,shape,etc.,to study the bridge box structure liquid gas phase transition from thermostat test device;(3)Using finite element software ADINA established join PCM and PCM not added concrete box bridge structure finite element model sunshine temperature field numerical simulation analysis done comparing model results showed that PCM bridge structure by solar radiation is from the box thermostat to a good effect,validated the feasibility PCM concrete box bridge structure by solar radiation control;(4)Bridge box structure to carry out the gas phase transition from liquid thermostat test.Research on the liquid gas phase transition material itself thermodynamics,physical properties,thermal stability,since the thermostat of the most worry and self-PCM Volume thermostat performance results show that in the process of heat transfer,PCM can greatly improve the packaging unit heat transfer performance,and has good thermal stability.At the same time,and numerical simulation ADINA results are identical,since the thermostat box structure of the bridge is played a very good role thermostat,not only reduces the temperature peaks bridge box structure,but also so that the temperature rise rate slows down;Study PCM Bridge thermostat housing structure for solving performance problems due to the cracking caused by temperature differences sunshine,long-term performance guarantee structure,durability and safety are of great importance.In this paper,the bridge box structure for liquid gas phase change material from thermostat subsequent development provides theoretical and experimental basis.