西德LTG旋风除尘器除尘性能的测定与分析

目前,如何选择良好的除尘设备处理纺织生产中的纤维性粉尘,已引起各方面的极大重视。本文针对此问题,分析测定了从西德LTG公司引进的旋风除尘器的结构特点和除尘性能,以供选用LTG旋风除尘器时参考。     

In Situ Measurement of the Undisturbed Ground Temperature for Ground Source Heat Pump System

The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different methods are presented. The investigation was carried out in two cases. The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile. The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7~C. This difference is mainly caused by the circulation pump and ambient air to the fluid. Therefore, the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring. A smaller pump or deeper borehole or mild weather would result in a more correct temperature. Because the undisturbed ground temperature is affected by many factors. Whether or not these conclusions are correct to other areas, this would need further investigation.     

旋风除尘器阻力计算的新方法

本文根据旋风除尘器内部流场的理想模型,通过伯努里方程导出了旋风除尘器阻力计算的新公式,经实验表明该公式比其它计算式具有更简单、更精确的特点.     

密闭式冷却塔热质交换性能分析与建模

对密闭式冷却塔进行了热质交换理论分析,建立了数学模型,并对该数学模型进行实验验证,结果表明所建冷却塔模型在工程精度要求内是正确的。     

Performance and Optimization for a Ground-Coupled Liquid Loop Heat Recovery Ventilation System

Ground-coupled heat pumps(GCHP) arecommonly used in residential heating system. To mitigatethe boreholes temperature dropping with operating time, anew exhaust-air recharging system is developed. The newrecharging system can be used in three operational modes.In this paper, a ground-coupled heat recovery ventilation(HRV) model is discussed. A thermal model is set up tofind the optimal brine flow rate and heat transfer allocationratio between exhaust and supply coils for maximum heatrecovery efficiency. Contrary to the conventional liquid-loopHRV systems, the brine temperature entering the exhaustcoil never goes blow zero(0℃), and hence defrosting isneedless in the ground-coupled HRV system. This can makethe ground-coupled HRV system over 20% more efficientthan a conventional HRV system at low outdoortemperatures.     

旋风除尘器分割直径(d_(c50))计算方法探讨

旋风除尘器具有结构简单、投资低、操作维护方便的特点,能处理常温或高温的含尘空气,是19世纪后期以来,工业上广泛使用的一种除尘设备。本文通过分析旋风除尘器气固分离机理和临界粒径的计算理论,对现有分割直径d_(c50)的计算方法作了探讨。认为d_(c50)的平衡位置应在轴向速度为零的滞留面上,位置高度力h_(c50)由气流流量分布确定,即过h_(c50)的水平截面将滞留面分成流过的气流量相等的上下两部分。     

土壤源热泵机组冬季供热性能的数值模拟与实验研究

分析热泵机组各部件参数之间的相互关系和运行特征，建立了可快速准确地模拟热泵机组动态过程的数学模型，并对土壤源热泵系统性能进行了数值模拟，其结果与实验测试值吻合较好。实验和模拟结果表明：上海地区土壤源热泵机组的制热性能系数COPh基于为3．1左右，优于风冷热泵机组，是一项有效的节能技术。     

Thermal Analysis of the Ground Properties with a Single Borehole Heat Exchanger

The effect of ground properties with heatconduction between soil and ground loop heat exchangers (GLHEs) has been analyzed. A finite line source model proposed by Cui, Yang, and Fang is used. Far field radius is defined. The analyses for a 1.5 m borehole line source in three kinds of soil conditions: damp and breeze (D. B.),damp and heavy (D. H.), and saturated and heavy (S. H.)are carried out. The results of the comparisons show that in the condition of continuous operation, the variation of the far field radius is related to soil thermal conductivity. The rate of heat transfer will decrease after long time operation.And then soil condition will not influence the far field radius obviously.     

Study of Performance on Recharging the Borehole by Means of Exhaust-air Energy

In this paper, the performance analysis of recharging the borehole by means of exhaust-air energy is carried out. The results show that a vertical borehole used as heat source for a Ground Source Heat Pump (GSHP) can be recharged in high efficiency. With equal heat transfer capabilities of exhaust-air coil and borehole collector, the system provides a maximum overall efficiency. However, due to ground infinite capacity, the optimum brine flow rate is different from conventional twoexchanger system. The recharging system provides two peak overall efficiencies when the capacity ratio Cr = 5 for laminar flow and Cr = 15 for turbulent flow respectively.The overall efficiency is independent of exhaust-air temperature and undisturbed ground temperature,although the fluid properties depend on temperature. In practical system lower ethyl percentage brine should be chosen if the freezing point meets the system request,which can provide a higher overall efficiency.     

土壤热源热泵系统垂直U形埋地换热器传热过程及合理间距的分析

利用传热理论，提出了土壤热源热泵垂直U型埋地换热器的等效换热器，并通过传热热阻分析，得到：埋地换热器在土壤中的取热过程，热阻的主要成分是土壤和塑料管壁。在换热强度为单位管长40W／m（单位埋孔长度80W／m），类似上海地区的气象与地质条件下，对50m深的埋地换热器孔中心间距至少为5－6m，才能保证换热器之间相互不受干扰。