热声制冷机回热器的现状及展望

概括介绍了目前热声热机常用热声研究理论及常见类型的热声回热器。重点综述了目前常用回热器研究理论及实验研究进展,针对不同种类回热器进行简单分析对比。基于热声回热器发展的现状对回热器今后研究发展趋势进行了展望。     

焦炉加热系统流量分配的数值仿真

 基于焦炉蓄热室的结构特点以及内部的流动过程,以质量守恒定律和动量守恒定律为基础,建立了焦炉蓄热室的小烟道及斜道区域的三维数理模型。利用数值模拟的方法对模型进行求解,揭示了蓄热室内气体流动的规律,计算出小烟道区域的相对压力分布以及篦子砖出口处和斜道出口处的气体流量分布。研究结果表明：从机侧到蓄热室中心处,相对压力值逐渐增大。在相同规格条件下,靠近蓄热室中心处的篦子砖出口流量偏大。由于结构的对称性,焦侧蓄热室的流量分布规律与机侧蓄热室的规律一致。合理的布置篦子砖规格有利于蓄热室长向加热均匀性。从机侧到焦侧,斜道出口的流量呈逐渐增大的趋势。而两侧炉头因其散热量比较大,故其气体流量较之中部立火道有所增大。     

复叠系统壳管式回热器的设计研究

回热器是复叠系统中的重要附属换热器,本文采用专业传热计算软件从流道布置方式、管程数等方面对影响回热器换热系数的因素进行研究,阐明壳管式回热器适宜的结构型式。     

玻璃熔窑蓄热室腔道设计的改进

对全分隔式、全连通式和组合连通式3种不同类型蓄热室腔道的构造特点及其优缺点进行了剖析。用实例对蓄热室腔道常规分隔做法的缺点进行了分析,提出了采用＂横向分隔墙微调错位＂法改进蓄热室腔道设计的具体措施。     

催化裂化再生器外取热器换热过程理论分析

从热量来源 (不从传热 )角度在理论上对目前催化裂化再生器各种外取热器作了分析 ,给出了对流热和“扩散热”的计算式。研究了各种外取热器的换热效率及计算方法 ,并找出了取热器内温度明显低于再生温度 (即使在入口处也如此 )的原因 ,进而提出了改进措施。研究结果表明 ,取热器本体内传热基本上受“扩散”控制 ;催化剂循环对取热器的作用主要归于对供剂起始温度的影响 ;用流化气体使供剂管路内催化剂扩散可提高取热量 ;各种外取热器的性能差别主要表现在供剂温度上 ;供剂管路的设计和操作状态 ,对取热器内温度可产生达 10 0℃的改变 ,从而影响取热器的负荷。     

焦炉加热自动控制系统的应用

介绍了采用蓄热室顶部温度控制焦炉自动加热系统的原理、特点及应用情况。结果表明系统投用后,有效提高了焦炉炉温的稳定性,使焦炉炼焦耗热量和焦炭吨焦耗煤气量得到明显降低。     

重油催化裂化装置再生器改造开大型作业孔引出问题的探讨

对140万t／a重油催化裂化装置利用UOP技术进行技术改造施工过程中在再生器危险段器壁开大型作业孔引出的问题进行技术探讨，通过计算论证了再生器器壁开大孔作业的可行性。     

Design and manufacturing of travelling wave thermo-acoustic engine with varying regenerator length

ABSTRACT

Thermo-acoustic engines are devices suitable to convert heat energy into acoustic energy and vice versa. In this paper, travelling wave thermo-acoustic engine was designed and fabricated for the operating conditions of 30?bar mean pressure of working fluid (Air, Helium, Hydrogen, Nitrogen) and 500°C hot side temperature. The regenerator was made up of the can(s) of stainless steel SA-347and can be adjusted to achieve the required length. The access to change wire mesh size and its length enables to reduce the test set-up time and to enhance flexibility during experimentation. The modified secondary cold heat exchanger was developed for effective heat extraction from the working fluid and the effect of modified regenerator on the intensity of the thermo-acoustic power was also addressed. The present study shares the suitable alternatives for material selection, design considerations and preliminary estimation of heat exchangers at the operating temperature and pressure. It provides initial dimensions and enables to make a prototype.     

Magnetic refrigeration: a promising new technology for energy saving

Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magnetocaloric effect. The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative refrigeration). In this paper, attention is directed towards the near-room-temperature range. We compare the energetic performance of a commercial R134a refrigeration plant to that of a magnetic refrigerator working with an AMR cycle. The comparison is carried out by means of a mathematical model. In these simulations, we consider different solid magnetic refrigerants, namely, Gd, Gd_0.95Dy_0.05, Gd_0.9Tb_0.1,Gd₅Si₂Ge₂, MnAs_0.9Sb_0.1, and MnAs_0.95Sb_0.05. We compared two different geometries of the regenerator: a porous medium and a flat plate. In the former, the Coefficient of Performance (COP) of the AMR cycle is better than that of the vapour compression plant only in the low mass flow-rate range. Whereas in a flat plate regenerator, the COP of the AMR cycle is better than that of the vapour compression plant only in the high mass flow-rate range.     

敞开式太阳能集热/再生器的理论模型及性能分析

对敞开式太阳能集热再生器建立理论解析模型,理论求解发现溶液在常温下再生时存在一个最佳单位面积流量使单位面积蒸发率最大。溶液入口温度和室外风速是决定最佳流量值的2个最重要参数,溶液浓度和太阳辐射强度对最大蒸发率影响最明显。当溶液出口温度低于入口温度时,最佳流量不存在,溶液流量越大再生效果越好。当室外风速为2m/s时,溶液再生蒸发率最大。文章全面揭示了影响敞开式集热/再生器性能的各项因素。