导流板渗透式太阳能空气集热器热性能研究

设计一种导流板渗透式太阳能空气集热器并对其进行试验研究。结果表明,该带导流板的渗透式太阳能空气集热器的出风口温度和集热效率均明显高于传统的太阳能空气集热器,集热效率在相同条件下提高约20%。利用Fluent软件对集热器内部流场进行数值模拟,结果表明该种集热器内部的温度场和速度场分布较均匀,吸热板和空气能够进行很好的对流换热。     

平板式太阳能空气集热器流道改进的试验研究和数值模拟

对传统平板式太阳能空气集热器的流道进行了改进,把对角型进出口流道改为多进出口式流道。对改进的集热器的性能进行了试验测试。新的进出口流道消除了吸热板和空气换热不均的现象,出口温度提升明显。在相同条件下,集热器的瞬时效率增加约20%。用CFD方法对集热器内部的流场结构和传热进行的数值模拟对比表明,传统集热器内部存在流动死区,中心截面温度分布不均匀,吸热板上有局部的高温区域,改进后的集热器流场和温度场分布得较均匀。     

高温太阳能吸热管在非均匀热流下的温度研究及结构优化

对腔式管状集热器在非均匀受热条件下进行温度场和热应力场的模拟.研究发现周向温差的不同造成吸热管的热变形分布不同,且吸热管后半段热变形最大;同时,太阳能辐射量随时间变化导致热流密度和吸热管壁面上的周向温差都在发生变化.鉴于此,分别从腔式集热器吸热管的结构、工作介质物性等方面入手以解决非均匀热流带来的形变问题.通过改变吸热...     

分析太阳能平板集热器吸热板芯传热性能的一种简易方法

该文通过对太阳能平板集热器吸热板芯的传热分析。导出了一种能计算集热器吸热板温度场分布的简易方法,通过与有限元数值计算方法得出结果的对比。表明这种方法是可靠的,可以用于分析吸热板结构。气象参数等因素对太阳能集热器传热的影响。以利于优化集热器结构。     

通用零件拼装式太阳能空气集热器

本实用新型是一种通用零件拼装式太阳能空气集热器。它的特征是:集热器阵列的拼装体主要由上下两个网格形桁架组成,桁架是由通用的桁条构成,上下网格形桁架的交叉点,以直角连接板相互连接,在上桁架的上阶梯形口处放置透明盖板。底边缘装有带有空气夹层的吸热体,下桁架上装有保护背板,保护     

装有旋流板的脱硫喷淋塔流场数值模拟研究

湿法脱硫喷淋塔内流场的分布对脱硫效果有着较大的影响,为解决脱硫塔内流场不均匀性问题,提出一种在脱硫塔内加装旋流板的方法,采用Realizable k-ε模型、DPM模型进行数值模拟,比较分析内部无旋流板结构的喷淋塔以及塔内分别加装1~3层扰流板且喷淋层采用高位布置的情况。结果表明,无旋流板时,喷淋塔内烟气分布不均匀;加装旋流板后,喷淋塔内烟气流场改善效果明显:塔内横截面烟气速度标准差值从2.375最低可降到1.056。综合分析脱硫场内流场、温度场和压力场,发现加装2层旋流板后塔内流场及温度场分布较为理想,有助于提高脱硫效率。     

圆柱阵列式太阳能空气集热器性能研究——应用于溶液除湿空调系统再生

提出将太阳能空气集热器加热的空气用于除湿冷却空调系统再生的想法,并为了提高集热效率,设计了一种圆柱阵列式空气集热器.通过实验数据分析,圆柱阵列集热器的最高效率可达到0.50～0.74,并整理出最高热效率随无量纲柱距(s/d)和无量纲柱高(h/d)变化的关联式.运用集热器热平衡模型得出PZ3-2.5型集热器的集热效率数学模型.对比实验结果,运用CFD软件模拟圆柱阵列集热器内的流场、温度场,从而突破实验研究的局限.通过对模拟数据分析,得出PZ7-11.25型圆柱阵列集热器的对流换热准则方程.     

新型太阳能空气集热器瞬时效率影响因素分析

选取一种新型抛物线型波纹吸热板太阳能空气集热器作为研究对象,建立其数学模型和物理模型,利用ANSYS(有限元分析)14.0数值模拟软件,模拟空气集热器入口空气温度、吸热板涂层、某天不同时刻、波纹布置方式、空气流动方式以及吸热板波纹幅值对空气集热器换热特性及瞬时效率的影响。结果表明:吸热板入口空气顺流流动的温度越低、横向抛物线型波纹板上使用选择性吸收涂层会使得其吸热板平均温度降低,瞬时效率增大,在入口空气流速2.0 m/s时,使用选择性吸收涂层使得瞬时效率最大达68.5%。另外,空气集热器的瞬时效率随时间的推移先增加后减小,在13时时,效率最大达61.8%;吸热板波纹幅值的增加提高了空气集热器的瞬时效率且增幅逐渐减小,在幅值h=10 mm时,效率最大达75.4%。     

太阳能空气集热器吸热板结构优化及其数值模拟

文章提出了一种新型抛物线型吸热板结构的太阳能空气集热器,建立其数学模型和物理模型,运用ANSYS数值模拟软件,对不同入口流速和倾角下集热器内空气换热特性进行数值模拟。结果表明:随着流速的增加,3种吸热板集热器瞬时效率逐渐增加;随着倾角的增加,集热器瞬时效率先增加后减小,在倾角30°时最大;对比传统平板和三角波纹吸热板结构,抛物线型空气集热器具有较高的瞬时效率和较小的压损。     

太阳电池生产用管式扩散炉的数值模拟————匀流板对流场的影响

以晶硅电池生产用管式扩散炉的内部流体状况为研究对象,用计算流体力学方法对管式扩散炉进行数学建模及流体力学数值模拟计算;对扩散炉内放置与未放置匀流板的流场状况进行对比研究;分析匀流板对扩散炉内部温度场、速度场、密度梯度场的影响及成因;认为装有匀流板的扩散炉内流体的速度场可给予硅片更为充足的磷源;发现匀流板附近存在着复杂的涡流区,认为该涡流区是决定扩散炉内温度场分布均匀程度的根本原因与关键因素。     

Performance of a double pass solar air collector

Double pass counter flow solar air collector with porous material in the second air passage is one of the important and attractive design improvement that has been proposed to improve the thermal performance. This paper presents theoretical and experimental analysis of double pass solar air collector with and without porous material. A mathematical model has been developed based on volumetric heat transfer coefficient. Effects of various parameters on the thermal performance and pressure drop characteristics have been discussed. Comparison of results reveals that the thermal efficiency of double pass solar air collector with porous absorbing material is 20-25% and 30-35% higher than that of double pass solar air collector without porous absorbing material and single pass collector respectively.     

水在玻璃管真空管太阳集热器热性能计算与分析

在水在玻璃管式全玻璃真空管集热器能量平衡分析的基础上，推导了集热器热损系数、效率因子等性能参数计算公式，理论计算结果与实验数据吻合良好。计算分析表明，真空管热损系数与吸热管温和环境温度之差是非线性关系，将两者的计算关系式按环境温度分段整理将使计算结果更接近实际；随着吸热管内对流换热系数的增大，其对效率因子和效率的影响逐渐减小，这说明对于水在玻璃管连接方式而言，为得到较大的管内对流换热系数而将流速过度提高是没有必要的；涂层发射率对集热器的热损系数和效率影响较大，降低涂层发射率是提高集热器效率的有效途径。     

Radiative Property of Absorbing Materials and its Collection Efficiency

Based on the previous research of the plate-type solar collector by the author, the analysis of the relationship between the spectral radiative property of the absorbing and transparent plates and their collector efficiency is firstly discussed on a simplified solar collector model. This analytical technique is then applied to evaluate the performance of water solar collector in practical use and the performance of five sorts of the commercial solar collectors are compared each other on both the collection efficiency and equilibrium temperature. Consequently, it is made clear that those solar collectors in Japan are of excellent quality of high collection efficiency.

Secondly, the performance of a unit-type air solar collector with carbon fiber sheet (CF-sheet) as the absorbing material, which was developed by the author in cooperation with a company, is analyzed and examined in the same way as above. Lastly, a large scale house-type air solar collector is tested, and this type of solar collector using carbon fiber' might be one of the most feasible methods to use solar energy in the industrial field including cost-performance.     

Comparative study of air heating solar collectors

Three types of conventional solar air heater are designed such that their heat absorbing areas and the pressure drops across them are equal for equal air mass flow rates per unit collector area. The results of thermal performance tests conducted simultaneously on these collectors, under the same environmental conditions, are presented.     

Collector efficiency of upward-type double-pass solar air heaters with fins attached

The collector efficiency of upward-type double-pass flat plate solar air heaters with fins attached and external recycle is investigated theoretically. The double-pass device was constructed by inserting the absorbing plate into the air conduit to divide it into two channels (the upper and lower channels). The double-pass device introduced here was designed for creating a solar collector with heat transfer area double as well as the extended area of fins between the absorbing plate and heated air. Moreover, the advantage of external recycle application to solar air heaters is the enhancement of forced heat convection strength, resulting in considerable device heat transfer performance improvement. This advantage may compensate for the remixing at the inlet which decreases the heat transfer transfer-driving force decrement (temperature difference).     

改进型微热管平板太阳能空气集热器性能分析

近年来,以空气作为换热介质的太阳能集热器越来越受到重视。本文以微热管阵列为核心传热元件,设计并搭建了改进型微热管平板太阳能空气集热器性能测试系统。通过实验研究了不同空气流量和不同进口温度对集热器集热性能的影响,获得相应参量对集热器的出口空气温度、集热效率和微热管阵列蒸发段温度的影响特性,分析对比了改进前后集热器的集热性能,得到了集热器效率的归一化曲线。实验结果表明,改进型微热管平板太阳能空气集热器在夏季240 m³/h空气流量时集热性能最佳,改进后的集热器相比原集热器在夏季的平均集热效率最高同比提升13.8%;在240 m³/h风量下的平均集热效率最高达到了74%,对应集热器的压降为9.2 Pa。     

Exergy analysis of single‐flow solar air collectors with different configurations of absorber plates

In the current study, an experimental analysis of exergy performance for different absorber plates is done. Three types of absorber plates are supplied with different fin arrangements with a variable air mass flow rate. The exergy analysis to evaluate the exergy performance of the solar air heaters uses experimental data for conventional and finned solar air collectors with different arrangements of fins. The main aim of the current study is to compare the exergy performance of the conventional solar air collector with those equipped with fins. The introducing of the fins in different arrangements enhances the absorber surface area, which leads to increased heat transfer. Also, fins induce air turbulence in the flow field, which improves the exergy performance of solar air collector. It is found that the exergy reduces and exergy efficiency enhances with increasing the airflow rate. The traditional flat absorber plate has undesirable exergy loss and exergy efficiency for all ranges of airflow rates. Thus, the flat plate collector presents the most substantial irreversibility, for which the exergy efficiency is the least. However, the results show that the exergy efficiency of inclined staggered turbulators is higher than that of in‐line and staggered turbulators. The optimal value of exergy efficiency is recorded at nearly 77% for the solar air collectors equipped with inclined staggered turbulators compared with other types of configurations.     

全玻璃真空管太阳热水器数值模拟研究

基于FLUENT软件及TECPLOT软件,通过对均匀加热条件下的全玻璃真空管太阳热水器内流场及温度场的数值模拟,研究了热水器的对流换热与传质过程;分析了集热管倾角、真空管双面受热对热水器内流场及温度场的影响和真空管与水箱连接处、垂直等温面上的流体速度、温度分布。结果表明,在真空管与水箱连接处出现随机的涡流和真空管内出现分段的小环流,对传热传质过程不利,特别是对于带反射板的双面受热的集热器,应采取措施确保管内对流换热流动的有序性。建议加装导流板,并初步探讨了导流板的长度,确立了最佳板长模拟结构,为后续的理论研究与试验打下基础。     

Analyses of single and double exposure solar air heaters

This paper presents an investigation of the performance of single and double exposure solar air heaters. A conventional solar air heater consist of a flat passage between two metallic plates through which heating fluid (air) is made to pass. the conduction loss along the lengths of the plates in the direction of the air flow and the radiation loss of heat from the absorbing plate to the bottom plate have been incorporated in the analyses. the analyses consist of the exact solutions of the heat balance equations for the absorbing plate, bottom plate and the air stream. Analytical expressions for the plate and the air stream temperatures as a function of distance along the direction of air flow and some other parameters have been derived. It is found that the heat conduction effects are negligible in both the air heaters and the reradiation of heat from the absorbing plate to the bottom plate is also insignificant.