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| 1 | 内加热搅拌釜中改进型 INTER-MIG 桨的传热性能显示文摘通过实验与数值模拟,以水为工作介质,在直径D=0.5 m的内盘管加热搅拌釜中对双层正交排列的改进型INTER-MIG浆搅拌器不同转速下的温度场、盘管外侧的温度边界层及传热系数进行研究.结果表明,实验与数值模拟的温度误差在2 K以内;搅拌釜内温度从上到下、从内到外呈升高趋势,最大温差基本保持在1 K之内;根据实验数据拟合得盘管外侧传热系数的关联式为Nu=0.0337Re0.925Pr1/3(d/D)0.1(dco/D)0.5,计算与实测值的平均偏差为7.64%;盘管外侧温度边界层平均厚度为3.66 mm,在合理范围内. | 周勇军 蒋宾伟 卢源 陈明濠 | 2014 | 过程工程学报2014,14,3: | 6 |
| 2 | Influence of nanoparticle concentrations on flow boiling heat transfer coefficients of Al_2O_3/R141b in micro heat exchanger by direct metal laser sintering显示文摘Al_2O_3/R141 b + Span-80 nanorefrigerant for 0.05 wt.% to 0.4 wt.% is prepared by ultrasonic vibration to investigate the influence of nanoparticle concentrations on flow boiling heat transfer of Al_2O_3/R141 b + Span-80 in micro heat exchanger by direct metal laser sintering. Experimental results show that nanoparticle concentrations have significantly impact on heat transfer coefficients by homogeneity test of variances according to mathematical statistics. The heat transfer performance of Al_2O_3/R141 b+ Span-80 nanorefrigerant is enhanced after adding nanoparticles in the pure refrigerant R141 b. The heat transfer coefficients of 0.05 wt.%, 0.1 wt.%, 0.2 wt.%, 0.3 wt.%and 0.4 wt.% Al_2O_3/R141 b + Span-80 nanorefrigerant respectively increase by 55.0%, 72.0%, 53.0%, 42.3% and 39.9% compared with the pure refrigerant R141 b. The particle fluxes from viscosity gradient, non-uniform shear rate and Brownian motion cause particles to migrate in fluid especially in the process of flow boiling. This migration motion enhances heat transfer between nanoparticles and fluid. Therefore, the heat transfer performance of nanofluid is enhanced. It is important to note that the heat transfer coefficients nonlinearly increase with nanoparticle concentrations increasing. The heat transfer coefficients reach its maximum value at the mass concentration of 0.1% and then it decreases slightly. There exists an optimal mass concentration corresponding to the best heat transfer enhancement. The reason for the above phenomenon is attributed to nanoparticles deposition on the minichannel wall by Scanning Electron Microscopy observation. The channel surface wettability increases during the flow boiling experiment in the mass concentration range from 0.2 wt.% to 0.4 wt.%. The channel surface with wettability increasing needs more energy to produce a bubble. Therefore, the heat transfer coefficients decrease with nanoparticle concentrations in the range from 0.2 wt.% to 0.4 wt.%. In addition, a new correlation has been proposed by fitting the experimental data considering the influence of mass concentrations on the heat transfer performance. The new correlation can effectively predict the heat transfer coefficient. | Jianyang Zhou Xiaoping Luo Cong Deng Mingyu Xie Lin Zhang Di Wu Feng Guo | 2017 | Chinese Journal of Chemical Engineering2017,25,12: | 4 |
| 3 | 聚合釜传热性能的实验研究及数值模拟显示文摘基于CFD模拟与传热实验相结合的方法对5 L夹套聚合釜的传热性能进行研究。建立聚合釜的液固耦合稳态传热模型,获得釜内流体、夹套内流体及金属固体域内温度分布。开展传热实验对模拟结果进行验证,各对比点温度的最大相对误差在1%~5%范围内。通过模拟获得釜内外壁面传热系数及总传热系数,并关联出釜侧及夹套侧Nu的经验式。结果表明:釜内流体温度分布方差始终在0.002以下,固体域内和传热边界层温度梯度较大,传热边界层厚度约3.8 mm;实验范围内,入口温度和反应放热量对釜内温度的影响显著,入口流速次之,搅拌转速影响最弱;夹套侧传热系数远小于釜侧传热系数,提高夹套侧传热系数是提升传热性能的关键;实验用聚合釜外表面散热量与内外温差呈正比,比例系数约为3.031 W·K^-1。 | 王修纲 吴裕凡 郭潞阳 路庆华 叶晓峰 曹育才 | 2020 | 化工学报2020,71,2: | 2 |
| 4 | Experimental research on stabilities, thermophysical properties and heat transfer enhancement of nanofluids in heat exchanger systems显示文摘Stable TiO_2–water nanofluids are prepared by a two-step method, stabilities of nanofluids are investigated by precipitation method and transmittance method respectively, and thermal conductivities and viscosities are also measured. An experimental system for studying the heat transfer enhancement of nanofluids is established,and heat transfer and flow characteristics of TiO_2–water nanofluids in heat exchanger systems with a triangular tube and circular tube are experimentally studied. The effects of nanoparticle mass fractions(ω = 0.1 wt%–0.5 wt%) and Reynolds numbers(Re = 800–10000) on the heat transfer and flow performances of nanofluids are analyzed. Fitting formulas for Nusselt number and resistance coefficient of nanofluids in a triangular tube are put forward based on the experimental data. The comprehensive performances of nanofluids in a triangular tube are investigated. It is found that nanofluids in a triangular tube can significantly improve the heat transfer performance at the cost of a small increase in resistance coefficient compared with that in a circular tube, especially the resistance coefficients are almost the same between different nanoparticle mass fractions at turbulent flow. It is also found that the comprehensive evaluation index η decreases with Reynolds number at laminar flow but a critical maximum value appears at turbulent flow. | Cong Qi Maoni Liu Guiqing Wang Yuhang Pan Lin Liang | 2018 | Chinese Journal of Chemical Engineering2018,26,12: | 1 |
| 5 | Experimental study on thermo-hydraulic performances of nanofluids flowing through a corrugated tube filled with copper foam in heat exchange systems显示文摘Thermo-hydraulic characteristics of TiO_2-water nanofluids in thin-wall stainless steel test tubes(corrugated tube and circular tube) filled with copper foam(40 PPI) are experimentally investigated and compared with those in test tubes without copper foam. The effects of nanoparticle mass concentration on flow and heat transfer performances are investigated. In addition, the mutual restriction relationships between Reynolds number(Re), Nusselt number(Nu) and resistance coefficient(f) are discussed respectively. Also, the comprehensive coefficient of performance(CCP) between heat transfer and pressure drop is evaluated. The results show that core-enhancement region for heat transfer using experimental tubes filled with copper foam is notably different from that of tubes without copper foam. There is a corresponding Reynolds number(about Re = 2400) for the maximum CCP of each condition. And the heat transfer can be enhanced dramatically and sustained at 8000 ≤ Re ≤ 12000. | Yongliang Wan Runhan Wu Cong Qi Gang Duan Ruizhao Yang | 2018 | Chinese Journal of Chemical Engineering2018,26,12: | 1 |
| 6 | Experimental investigation and development of new correlation for influences of temperature and concentration on dynamic viscosity of MWCNT-SiO2(20-80)/20W50 hybrid nano-lubricant显示文摘In current research, MWCNT-SiO_2/oil hybrid nano-lubricant viscosity is experimentally examined. By dispersing 0.05%, 0.1%, 0.2%, 0.4%, 0.8% and 1% volume of MWCNTs and SiO_2 nanoparticle into the engine oil SAE 20W50, the temperature and solid volume fraction consequences were studied. At 40 to 100 ℃ temperature, the viscosities were assessed. The results indicated Newtonian behavior for the hybrid nano-lubricant. Moreover, solid volume fraction augmentation and temperature enhanced the viscosity enhancement of hybrid nano-lubricant. At highest solid volume fraction and temperature, nano-lubricant viscosity was 171% greater compared to pure 20W50. Existed models lack the ability to predict the hybrid nano-lubricant viscosity. Thus, a new correlation regarding solid volume fraction and temperature was suggested with R-squared of 0.9943. | Kazem Motahari Mohammad Abdollahi Moghaddam Mojtaba Moradian | 2018 | Chinese Journal of Chemical Engineering2018,26,1: | 1 |
| 7 | 循环射流混合槽内湍流强化传热数值模拟及射流层优化显示文摘循环射流混合槽(CJT)作为一种过程强化设备可以提高湍流的混合效率及反应选择性。为进一步提高其工业应用价值,对循环射流混合槽流场的传热能力进行分析并对其射流层数进行结构优化。在恒壁温的条件下,采用SST k-ω模型分析循环射流混合槽流场区域的非稳态流动传热特性。在充分湍流状态下研究了Re=3260~16303,射流层数M=5~9对循环射流混合槽壁面对流传热特性及流场传热特性的影响。结果表明,M=9时对流换热系数的变异系数C_(h)随Re增加而减少,壁面传热均匀性提高2.8%~19.3%;流场与温度场协同性随Re增加而增加,Re=16 303时的协同角为75.5o比Re=3260时减小约0.5°。Re=9782时C_(h)随M增加而降低,壁面传热均匀性提高2.7%~16.3%;速度矢量与温度梯度协同性随M增加而减小,M=9时全局协同性相较于M=5时降低了6.1%。当M=7时中心混合区与射流混合区的场协同角均在73°~74°之间,两区域流场间热量传递能力匹配程度较好;当M<7时中心混合区的协同性优于射流混合区,当M>7时射流混合区协同性优于中心混合区。研究Re及射流层数M对循环射流混合槽热量吸收和传递性能的影响,发现Re的变化对循环射流混合槽吸热量的影响大于射流层数M的变化。 | 禹言芳 孔令敏 孟辉波 石博文 柳东洲 吴剑华 | 2022 | 过程工程学报2022,22,11: | 0 |