工业炉蓄热燃烧系统的开发

蓄热燃烧技术是目前最先进的节能技术，宝钢技术中心结合宝钢的应用工况，自行开发了蓄热燃烧系统（包括蓄热烧嘴、蜂窝体与换向阀等关键设备），开发的系统在专门设计的中试炉上进行了试验，证明该系统性能先进，可以满足工业应用。     

蜂窝体蓄热室结构优化及软件开发

以蜂窝体蓄热室的结构优化为研究目标,模型采用的多目标优化以蜂窝蓄热体的温度效率和热回收率作为目标函数.,以空气流速,换向时间和蜂窝蓄热体的高度为优化变量,模型的计算采用线性加权法,对蜂窝体蓄热室的主要结构参数进行了优化设计,以保证气体在满足换热强度条件下,尽量减小阻力损失。并开发了蜂窝体蓄热室结构优化的软件。     

蓄热体结构分析及其内部气体流动特性的数值研究

介绍了不同几何结构蓄热体的比表面积和开孔率的变化情况,在以蓄热量相等为前提的情况下,分析和比较了蓄热小球和蜂窝体两类蓄热体的结构特性。利用CFD软件模拟了蓄热室内气流的轨迹,分析了不同形状蜂窝体的压力损失及中心线速度的变化情况,计算出不同形状蜂窝体内部气体的流动特性、压力分布和换热性能,为设计和选择合适的蓄热体提供了指导。     

多孔基无机玻璃-熔盐复合相变材料蓄热性能的实验研究

基于熔融浸渗法和黏结封装法,以多孔基作为基体材料,分别采用无机玻璃粉与熔盐作为相变材料开展实验,探究储热样本的最佳制备工艺流程。考察了复合相变蓄热体的显微结构及物相组成特征,分析了复合相变蓄热材料的质量损失率,并对蓄热体进行蓄热性能分析及高温抗压强度测试。实验结果表明,采用黏结封装法,以氯化钠作为相变材料,加盖圆柱形三角孔蜂窝陶瓷基体作为载体,设定6.5℃/min的升温速率,烧结温度至800℃,保温30 min,可制备蓄热性能较为优异的复合相变蓄热材料。复合相变蓄热材料的蓄热密度为445.5 kJ/kg,该蓄热体在800℃条件下高温抗压强度达到75.9 MPa,具有良好的蓄热性能和力学性能。     

高效长寿蓄热体的研究与开发应用

蓄热体作为蓄热室余热回收设备的核心材料,承担着冷热介质热量传递的任务,是蓄热式燃烧技术能否高效运作的关键。本文对蓄热体尺寸、形状、热工特性和材质进行了研究,并在分析韶钢蓄热式加热炉生产实践的基础上,寻找蓄热体寿命低的原因,实验高效长寿蓄热体材料,介绍了应用的经验与效果。     

蜂窝蓄热式空气单预热烧嘴换热特性的热态试验研究

采用热态模拟方法对蜂窝蓄热式空气单预热烧嘴的换热特性进行了试验研究，通过对试验数据的分析，得出了蓄热式烧嘴换热性能与空气流量、换向时间的关系及蓄热室内温度的分布特点等，确定了最佳换向时间、单位蓄热体体积的合适流量和蓄热室的适宜长度等。     

蜂窝蓄热体易损原因分析及其解决措施

针对加热炉采用的蜂窝蓄热体出现的问题,从材质性能、炉内实际情况、结构等方面分析出其破损原因。并设计一种新型的蓄热式烧嘴,通过热态试验对其换热性能与普通蓄热烧嘴进行了比较,表明采用这种新型烧嘴是解决蓄热体破损的有效措施之一。     

蓄热体余热回收换热器强化传热实验研究

利用蓄热式热热交换理论和高温空气燃烧技术的原理,在热态实验基础上建立了蜂窝陶瓷蓄热体的性能研究实验.结果表明,热效率及温度效率随换向时间的增加均呈现先上升后下降的趋势,存在一个最佳换向时间,即热效率和温度效率随着长度的增加而增大,但阻力损失也随之增大;同时存在一个最佳气体流速使蓄热体效率与经济效益达到最佳值;蓄热体的平均温度与气体出口温度均随着换向周期数的增加而升高;对于给定几何外形尺寸的蓄热体,四边形孔格结构的蓄热体具有较大的比表面积,流动性更好,具有更高的温度效率和热效率.     

管壳式蓄热装置的设计及蓄热单元三维数值模拟与优化

为弥补太阳能间歇性的缺点,设计了管壳式蓄热装置并建立了一个三维的、非稳态的、液态石蜡包含自然对流的相变蓄热装置模型,在该模型中取一个蓄热单元进行模拟研究。蓄热单元为圆柱体,内部放置石蜡,中心位置为传热管,热水通过传热管和传热管上的翅片对石蜡进行加热。对蓄热单元的蓄热过程进行了三维数值模拟,分别分析比较了有无自然对流条件,不同蓄热单元放置,以及增加内外翅片情况下蓄热单元的蓄放热性能,研究结果可为蓄能装置及集成系统的开发提供理论依据。     

新型板式相变单元蓄热特性的理论及实验研究

在太阳能储能装置中，保持相变储能单元组配灵活性不受影响的同时，为了增强板式相变单元的蓄热性能，对普通的矩形板式单元进行结构优化，设计了新型的梯形体单元，并利用理论分析得到了最优梯形体结构的理论解。将理论分析结果进行实验验证，研究表明：设计出的新型梯形体板式单元不仅能充分利用相变材料本身的熔化特性提升储能装置的蓄热性能，还能提高空间利用率。在研究范围内，换热流体流速的增大和温度的增加可有效地提高单元的换热效率，其中，流速为0.12 m/s时最优梯形体单元比之矩形单元的蓄热性能提升最明显。     

新型回热器结构设计及换热特性研究

回热器作为斯特林热机的关键部件,对于太阳能斯特林热机整机性能有着重要影响。为克服传统金属丝网回热器结构存在的填料单一,制造成本较高,工艺复杂问题,采用实用等温分析法,以回热器的长径比、通流面积、填料种类以及孔隙率各项回热器参数为基础,设计了一种新型斯特林热机回热器,该回热器具有轴向压降小,换热性能高,结构稳定,加工制造简单的特点。开展了新型回热器和传统金属丝网回热器的换热性能对比研究,采用振荡条件下的局部热平衡方法研究回热器的传热过程,对比传统金属丝网回热器和新型回热器的温度变化,速度变化以及压力变化。结果表明:在整体孔隙率相同的条件下,新型回热器和传统金属丝网回热器相比,整体启动速率相似,但新型回热器压降减少0.04 MPa,速度出现分段式变化,有利于回热器的换热和结构稳定。因此,新型回热器不但在结构上优于传统金属丝网回热器,在换热特性上也优于传统金属丝网回热器。     

An experimental study of a forced flow solar collector/regenerator using liquid desiccant

One of the main components of a liquid desiccant cooling system is the regenerator. In a liquid desiccant air conditioner, outside air is dehumidified by liquid desiccant and cooled within the absorber. The diluted desiccant solution thus obtained has to be concentrated for reuse, by passing through the regenerator and the cycle is, consequently, repeated. The regenerator used in this application is a forced parallel flow type solar collector/regenerator. The regenerator has been designed and optimized and the prototype of the solar collector/regenerator has been built and tested. Calcium chloride has been used as the absorbent solution. The results of the tests conducted as a parametric analysis indicate that the air and solution mass flow-rates and the climatic conditions affect the regenerator performance. Furthermore, a comparison between the experimental data obtained and a previously developed model for a forced parallel flow solar collector/regenerator reveals that the experiments are in good agreement with the model predictions. Finally, it was concluded that the proposed solar collector/regenerator performs satisfactorily under the summer conditions of Adelaide, Australia.     

Modelling of the thermal behaviour of a solar regenerator for open-cycle cooling systems

This paper describes a mathematical model of a solar regenerator, which could be used in either an open-cycle desiccant-cooling system or an open-cycle absorption-cooling system. The model has been validated by experimental data from the published literature. The effects of the variation of the values of various parameters on the performance of the regenerator has also been analysed.     

Theoretical study of tilted solar still as a regenerator for liquid desiccants

A closed type (tilted solar still) solar regenerator has been studied in application to regeneration with liquid desiccants. Essentially, it consists of a flat blackened, tilted surface with a transparent glazing as a covering. The absorbent solution which is to be regenerated trickles down as a thin film over the absorber and is heated by solar energy. The water vapor that evaporates from the liquid film is condensed on the under side of the glass cover and the solution leaving the regenerator becomes strong. A simple expression is derived, in this paper, to estimate the mass of water evaporated from the weak absorbent solution as a function of climatic conditions and initial conditions of the absorbent solution. A comparison is also made with a forced flow air circulation regenerator, and it was found that the closed type regenerator may be used for regeneration only in hot, humid climates.     

Thermodynamic analysis of a Stirling engine including regenerator dead volume

This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling engine with linear and sinusoidal variations of the volume. The regenerator in a Stirling engine is an internal heat exchanger allowing to reach high efficiency. We used an isothermal model to analyse the net work and the heat stored in the regenerator during a complete cycle. We show that the engine efficiency with perfect regeneration doesn’t depend on the regenerator dead volume but this dead volume strongly amplifies the imperfect regeneration effect. An analytical expression to estimate the improvement due to the regenerator has been proposed including the combined effects of dead volume and imperfect regeneration. This could be used at the very preliminary stage of the engine design process.     

新型档位蓄热器的开发与研究

研究开发了一种可应用在高温空气燃烧（HTAC）技术中的新型蓄热器--档位蓄热器.档位蓄热器吸收了回转式蓄热器的思想,结合了切换式蓄热器的特点,将二者的优势融合在一起,其外观类似于回转式蓄热器,但运动型式却由回转式蓄热器的连续运动变为间歇转动,且具有了新型的密封结构.对档位蓄热器的基本工作原理、具体设计方案、实验研究及应用前景进行了详细介绍.研究结果表明档位蓄热器具有以下特点：可实现对炉窑的连续供气,保证了炉内火焰的稳定性,从而使炉内工况不易波动;另外系统的漏风率较低,阻力损失也较低,并且设备紧凑、操作安全可靠,易于实现标准化生产.实验研究的结果证明该蓄热器的温度效率可达88%,热效率可达77%.     

空心圆柱蓄热体三维非稳态传热与流动的模拟研究

通过对整砌空心圆柱蓄热室的建模研究,对YC与FZ的温度场与流场进行了对比分析,所建模型具有一定的可信度,其反应温度场及流场诸多现象的可视化结果对实际工程应用有一定借鉴作用。     

Modeling and simulation of solar-powered liquid desiccant regenerator for open absorption cooling cycle

This paper presents the modeling and simulation of solar-powered desiccant regenerator used for open absorption cooling cycles. The input heat, which is the total radiation incident on an inclined surface, is evaluated via a solar radiation model in terms of the location, day of the year, and time of the day. Calcium Chloride (CaCl₂) is applied as the working desiccant in this investigation. The solar radiation model is integrated with the desiccant regenerator model to produce a more realistic simulation. A finite difference method is used to simulate the combined heat and mass transfer processes that occur in the liquid desiccant regenerator. The system of equations is solved using the Matlab-Simulink platform. The effect of the important parameters, namely the regenerator length, desiccant solution flow rate and concentration, and air flow rate, on the performance of the system is investigated. It has been found that the vapor pressure difference has a maximum value for a given regenerator length. It is also shown that for specified operating conditions, a maximum value of the coefficient of performance occurs at a given range of air and solution flow rates. Therefore, it is essential to select the design parameters for each ambient condition to maximize the coefficient of performance of the system.     

A thermoacoustic engine capable of utilizing multi-temperature heat sources

Low-grade energy is widespread. However, it cannot be utilized with high thermal efficiency directly. Following the principle of thermal energy cascade utilization, a thermoacoustic engine (TE) with a new regenerator that can be driven by multiple heat sources at different temperature levels is proposed. Taking a regenerator that utilizes heat sources at two temperatures as an example, theoretical research has been conducted on a traveling-wave TE with the new regenerator to predict its performance. Experimental verification is also done to demonstrate the benefits of the new regenerator. Results indicate that a TE with the new regenerator utilizing additional heat at a lower temperature experiences an increase in pressure ratio, acoustic power, efficiency, and exergy efficiency with proper heat input at an appropriate temperature at the mid-heater. A regenerator that uses multi-temperature heat sources can provide a means of recovering lower grade heat.     

Numerical prediction of the instantaneous regenerator and in-cylinder heat transfer of a stirling engine

The paper is concerned with the study of the effects of the in-cylinder and regenerator heat transfer characteristics of a single-acting opposed-piston Stirling engine, with heater and cooler both omitted, for which a simulation model has been developed. The engine thermodynamic cycle is divided into a number of time-steps, and a system of nonlinear ordinary differential equations, which describe the energy balances over the three basic control volumes (hot and cold cylinders and regenerator), is solved numerically. Empirical correlations are used to determine the instantaneous heat transfer coefficients in the regenerator (flow across a porous medium) and inside the cylinder space (gas confined in a cylindrical volume with a moving boundary). Numerical results from the model are presented.