【作者】 孟祥睿；

【导师】 魏新利；

【作者基本信息】 郑州大学 ， 化学工艺， 2009， 博士

【摘要】 本文以内燃机尾气余热驱动的吸附制冷系统为背景,围绕如何提高吸附床传热传质性能和系统可靠性,开展了高效复合吸附剂、复合吸附剂与换热壁面连接方式以及单管吸附床和新型制冷单元的研究。主要研究成果如下:1、研制了一种在一定温度下烧制而成的固化分子筛复合吸附剂,该吸附剂以分子筛为主吸附剂,其配比（质量份）为:分子筛:凹凸棒粘土:发泡剂:膨胀石墨=100:40:15:30。2、利用正交试验和逐步回归法导出了凹凸棒粘土、膨胀石墨和发泡剂的添加量,以及烧制温度这4个因素与复合吸附剂导热系数的经验式为:λ=0.379-0.857a-0.771b+0.468c-8.6×10^-5d+1.481a²+1.515b²+0.0336c²W/（mK）采用加权评价法对吸附剂的吸附性能进行了评价与对比,得到上述4个因素与吸附性能经验式为:x=9.038-0.487a-8.982b-1.770c-0.001d-4.995bc+16.799b²+0.0152a²b-0.435a²c+0.512b²c式中:a、b、c分别为凹凸棒粘土、发泡剂、膨胀石墨相对于分子筛的质量百分比d为烧制温度单位℃经实验验证上述两经验式可用于预测该类吸附剂导热系数、吸附性能,并为的吸附床工程设计提供参考。3、提出使用胶粘剂将复合吸附剂与金属换热壁面粘结在一起的方法。该方法不仅能够有效减小吸附剂与金属换热壁面间的接触热阻,而且能够有效减小因两者间因线性膨胀系数不一致而引起的热应力。研究结果表明添加纳米SiC的硅橡胶胶粘剂是一种基本适合本研究工况的胶粘剂。4、利用所开发的复合吸附剂和提出的粘结方法,制作了单管吸附床制冷实验台,并对效果进行了研究与考核。实验证明:散装条件下,环状固化分子筛复合吸附剂较环状纯分子筛吸附剂缩短响应时间约12.9%;采用添加纳米SiC的硅橡胶粘结剂将吸附剂与金属换热壁面进行粘结的方法较散装方法缩短响应时间27.4%。响应时间减少将有效缩短循环周期。5、借鉴热管和浮头式换热器原理,提出一种新型吸附制冷单元。并利用集总参数法和Simulink对由新型制冷单元组成的两床系统的运行规律、操作参数对吸附制冷性能的影响进行了数值模拟研究。研究表明:热源温度存在一个极值,当超过这个温度极值后,再提升热源温度反而要削弱系统的制冷能力;蒸发温度提高和冷却温度降低将有助于提高系统的制冷能力;系统的吸附/脱附时间比与循环周期有关,但通常都是吸附时间长一些,约占循环周期的60%左右;吸附剂导热系数的提高可以有效的提高吸附制冷系统的制冷性能。更多还原

【Abstract】 In order to improve the performance of adsorbent bed and reliability of adsorption refrigeration system driven by internal combustion engine exhaust waste heat,some research and exploration,which are focused on high-performance composite adsorbent,the installation method between absorbent and adsorbent bed, the performance of single-tube adsorbent bed and new refrigeration unit,were done. Main results are as follows.1.A zeolite-based composite absorbent was preparated and recommended,with the formula:13X zeolite 100（mass fraction）,attapulgite clay 40,blister 15,expanded graphite 30,350℃sintered;2.With the orthogonal test and stepwise regression method,the empirical was derived and validated by experiment,The equations about of the thermal conductivity and adsorption performance of composite adsorbent with the 4 factors above are as follows:Thermal conductivity:λ=0.379-0.857a-0.771b+0.468c-8.6×10^-5d+1.481a²+1.515b²+0.0336c² W/（mK） Adsorption performance（by weighted evaluation method）:χ=9.038-0.487a-8.982b-1.770c-0.001d-4.995bc+16.799b²+0.0152a²b-0.435a²c+0.512b²c Where a,b,c are mass percent of attapulgite clay,blister,expanded graphite,d is the sintered temperature（℃）.3.Bonding method is proposed to reduce the contact thermal resistance between the absorbent and the heat transfer surface of adsorbent bed.This bonding method can not only reduce the thermal stress,which is generated by the difference of linear expansion coefficient between the absorbent and the metal heat exchanger,but also can enhance the reliability of the adsorbent bed.The results of experiments show that the silicone rubber added nano-Sic is a good adhesive for sorbent and adsorbent bed.4.In the single-tube adsorption refrigeration test-bed,the effects to the adsorption refrigeration performance of composite absorbent and bonding methods are tested.The tests show that the response time by using composite adsorbent will be shorten about 12.9%than pure zeolite.The response time by using the new bonding methods will be shorten about 27.4%than bulk methods.This will effectively result in the cycle time of system be shorten.5.A new type of adsorption refrigeration unit and its application systems are proposed,which combines the features of heat pipe and the floating head heat exchanger.Lumped parameter method and Simulink are used to simulate the performance of system,which consists of two new units.The operation law of the adsorption refrigeration system and the influence of operating parameters to adsorption refrigeration system were studied.The results show that the capacity of refrigeration system will be weakened with the raise of heat source temperature when the heat source temperature overrun an extremum;the increase of evaporation temperature,or the decrease of cooling temperature,or the increase of thermal conductivity of sorbent,will help to improve the capacity of refrigeration system;The ratio between adsorption time and desorption time is related to the cycle periodic time, and the adsorption time is usually longer than desorption time,it takes up about 60% of cycle time.更多还原