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为改善工业微波加热过程中加热不均匀问题,通过仿真带有螺旋推进器管道式加热装置,研究螺旋转速、流体入口流速以及螺旋材料对加热均匀性的影响。通过结合麦克斯韦方程、传热方程以及连续性方程并结合动网格进行多物理场耦合仿真,结果表明增大螺旋转速温度变异系数先减小后增大,在层流状态下转速越大加热均匀性越好,在湍流状态下转速越大加热均匀性越差。入口流速与螺旋转速共同影响加热均匀性,会使温度变异系数在一定范围内波动。随着入口流速的增大螺旋转速对流体平均温度的影响逐渐减小。采用微波反射型材料的加热效果要优于微波穿透型材料。探究了不同因素对微波加热均匀性的影响,对液体材料微波加热的工业应用具有指导意义。 相似文献
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在研究感应加热基本理论的基础上,通过MATLAB及ANSYS有限元分析软件,对所设计的轴承内环感应拆装器进行了计算机仿真研究.通过对感应加热过程中拆装器内电磁场的计算机模拟,得出了磁场的分布规律,证明了涡流集肤效应的存在,为感应加热装置的设计奠定了基础. 相似文献
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本文介绍了谐振式曲轴弯曲疲劳试验及其动力学仿真模拟分析研究,根据谐振式曲轴弯曲疲劳试验机的试验原理,对这一试验装置进行仿真模拟,实现试验与计算的相互印证,并探索、寻求采用仿真计算简化试验流程的可能性。 相似文献
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A dynamic model of a room with a hot water baseboard heater is developed. In the modelling methodology used, a typical finned‐tube baseboard heater with its cover was divided into several control volumes. The mass, energy balance and momentum equations were formulated and solved for each control volume. The dynamic model was used to study the effect of important design and operating parameters on the heat output rate of the baseboard heater. Simulation runs showing the dynamic responses of airflow rates, air temperature from the heater, and hot water temperature are presented. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Simulation and experimental investigation of two hybrid solar domestic water heaters with drain water heat recovery
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In this paper, the performance of two solar domestic hot waters (SDHW) with drain water heat recovery (DWHR) units is investigated. Both SDHW systems are recently installed at the Archetype Sustainable Twin Houses at Kortright Center, Vaughan, Ontario. The first SDWH system in House A consists of a flat plate solar thermal collector in combination with a gas boiler and a DWHR unit. The second SDHW system in House B includes an evacuated tube solar collector, an electric tank, and a DWHR unit. Both systems are modeled in TRNSYS, and the models are validated by experimental data. The addition of the DWHR and the flat‐plate solar thermal collector would result in 1831 kWh of annual energy saving in House A. While the addition of the DWHR and the evacuated tube collector in House B would result in an annual energy saving of 1771 kWh. Subsequently, the models are used to investigate the performance of similar systems for five major Canadian cities of Halifax, Montreal, Toronto, Edmonton, and Vancouver. The conjunctions of solar thermal collectors with DWHR units are found most beneficial in Edmonton. It is also noted from experimental and simulated results that flat‐plate solar collector‐based water heater produced more thermal energy than the system based on the evacuated tube solar collector for all major Canadian cities. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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In this paper, interval number optimization and model predictive control are proposed to handle the uncertain-but-bounded parameters in electric water heater load scheduling. First of all, interval numbers are used to describe uncertain parameters including hot water demand, ambient temperature, and real-time price of electricity. Moreover, the traditional thermal dynamic model of electric water heater is transformed into an interval number model, based on which, the day-ahead load scheduling problem with uncertain parameters is formulated, and solved by interval number optimization. Different tolerance degrees for constraint violation and temperature preferences are also discussed for giving consumers more choices. Furthermore, the model predictive control which incorporates both forecasts and newly updated information is utilized to make and execute electric water heater load schedules on a rolling basis throughout the day. Simulation results demonstrate that interval number optimization either in day-ahead optimization or model predictive control format is robust to the uncertain hot water demand, ambient temperature, and real-time price of electricity, enabling customers to flexibly adjust electric water heater control strategy. 相似文献
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办公室和厂房供暖常采用蒸汽供暖或热水供暖。结合实际情况分析比较了两种供暖方式的优缺点。蒸汽供暖一次性投入较小,但使用维护费用较大;热水供暖和蒸汽供暖相比需增设一套热水循环装置、回水池和回水管路,但运行费用相对较少,且可最大程度地减少跑、冒、滴、漏现象的发生,从而可大大提高设备和材料的利用率,降低成本,最终起到节能降耗的作用,应广泛推广和应用。 相似文献
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An experimental investigation is carried out on a forced circulation solar water heater to assess its performance under various operating conditions. The system consisted of two identical collectors of total absorber area of 3.45 m2 and a storage tank of 200 litre capacity. Experiments were carried out during clear days with and without system loading for two water mass flow rates through the collector; namely 0.1305 kg/s and 0.06525 kg/s. The system was operated without thermostat control and with thermostat control at maximum and minimum settings. The collector efficiency improved with system loading. The improvement was better with increased hot water withdrawal from the system. 相似文献
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An experimental investigation has been carried out on a thermosyphon solar water heater. The system consisted of a flat-plate collector of 1.5 m2 absorber area with 21 tubes/m width and storage tank of 125 litre capacity. Experiments were carried out for both cloudy and clear weather conditions in winter and summer. The hourly system performance was evaluated for all test conditions. The final mean tank temperature was measured daily which enabled the calculation of the possible contribution of solar energy for domestic hot water supply in Basrah, Iraq (latitude 30.76°N). The system was tested at both no-load and loading conditions. Intermittent and continuous load was imposed, and system performance was evaluated for each condition. 相似文献
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This article experimentally and theoretically investigates a two-phase thermosyphon solar water heater. The performance of this innovative solar water heater at different solar radiation intensities and tilt angles are experimentally discussed. The results show the best charge efficiency of the system is 82%, which is higher than the conventional solar water heaters. The theoretical model is also developed using the thermal resistance-capacitor method. The simulation predictions agree well with the experimental data within an average error deviation of ±6%. Two methods for improving the performance of this heater, double fin tubes and nano particle, are proposed. The results show that charge efficiencies can increase 3% and 4%, respectively, according to the theoretical model. 相似文献
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N.M. Nahar 《Energy Conversion and Management》1983,23(2):91-95
Systematic studies have been carried out on collector-cum-storage type solar water heaters, and efforts were made to minimise heat losses so that this type of water heater can be used for getting hot water at 40°–45°C for taking baths in the early morning hours of the next day. This paper reports year round performace, the performance equation and economics of this new improved solar water heater. This heater can supply 100 litres of hot water at 60°–70°C in the afternoon, and 40°–45°C temperature can be retained till next day morning. Its efficiency is 70.1%. 相似文献