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Experimental Investigation of Heat Transfer in Microchannel with Inlet Cavitation Structure

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Journal of Thermal Science 2021年第1期30卷 294-301页

作者： yuan junfei WANG Lin WANG Zhanwei TAN Yingying Institute of Refrigeration and Air Conditioning Henan University of Science and TechnologyLuoyang 471023China

Heat transfer of R134 a through the microchannel with an inlet reentrant cavitation structure was investigated for high flux thermal management of electronic *** cavitating flow patterns,pressure,and heat transfer characteristics were studied in the range of effective heat fluxes from 0 to 138.4 W/cm2 with mass flow velocities from 2.12 to 5.23 m/s.A stable and ideal starting point of two phase flow and heat transfer was commendably provided by the inlet cavitation *** existed an axis deviation liquid jet after the *** refrigeration vapor was generated from the cavitation structure but liquidized at the downstream of the *** wall temperature along flow orientation presented an opposite trend under the test states with or without heat *** cavitation structure can significantly suppress the flow oscillation in microchannels and the outlet pressure fluctuation reduced about 72%compared with the fluctuation at the *** heat transfer coefficient had been distinctly impacted by heat flux at lower heat input and then maintained the value nearly constant of 11.0 W/(cm^(2)·K)with the critical heat flux of 88.4 W/cm2.

关键词： heat transfer cavitation structure flow pattern pressure oscillation microchannel

Energy and Exergy Analysis of a Cooling/Power Cogeneration Ejector Refrigeration System

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Journal of Thermal Science 2022年第2期31卷 448-462页

作者： YANG Mengke LI Xiuzhen WANG Lin yuan junfei WANG Zhanwei LIANG Kunfeng Institute of Refrigeration and Air conditioning Henan University of Science and TechnologyLuoyang 471023China

The organic Rankine cycle is introduced into the conventional ejector refrigeration(CER)system to establish the low-grade heat-driven cooling/power cogeneration ejector refrigeration(CPC-ER)system using the isobutane as the *** comparison with the CER system where external power is consumed by the circulating pump,the power output from the CPC-ER system is more than the power consumption of its circulating pump so that a portion of net power is derived from the CPC-ER *** on the mathematical model of thermodynamics,energy and exergy analysis of the CPC-ER system is carried out and compared with the CER *** results reveal that the equivalent coefficient of performance(COP)of the CPC-ER system is 41.14%to 71.30%higher than that of the CER system,and the exergy efficiency of the CPC-ER system is 1.32 to 1.49 times higher than that of the CER *** the power produced by the turbine and the total exergy output from the CPC-ER system approach the maximum,as the generating temperature in the generator is up to 80°*** CPC-ER system has the higher energy utilization efficiency than the CER system,and it is suitable for the cooling and power-required places with low-grade thermal sources.

关键词： ejector refrigeration exergy power consumption equivalent COP

The numerical simulation of the movements and thermal states of atomized metal droplets in the spray forming process

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Baosteel Technical Research 2009年第2期3卷 58-63页

作者： yuan Feng FAN junfei REN Sanbing LE Hairong ZHAO Shunli Advanced Technology Division Baosteel Research Institute Baoshan Iron ＆ Steel Co. Ltd. Shanghai 201900 China

Numerical simulation was performed in an atomizing chamber to investigate the movements and thermal states of the atomized metal droplets in the spray forming process. The velocity, temperature and solid fractions of metal droplets with different diameters and under different atomizing pressures were investigated. The results indicate that a higher atomizing pressure results in the increased flying velocity of the metal droplets and a decrease in the cone-shaped angle formed by their flight paths. Synchronously, the cooling of the metal droplets is accelerated and the time of the complete solidification process is shortened. Under the same atomization pressure, large metal droplets have a lower flying speed and a lower rate of temperature decrease in the atomizing chamber than small metal droplets. In addition, metal droplets flying along the edge of the atomizing region cool faster than those flying in the core region.

关键词： spray forming atomization pressure atomized metal droplet diameter numerical simulation

Serum amylase as a novel prognostic marker of organophosphorus poisoning:a retrospective study

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Emergency and Critical Care Medicine 2024年第3期4卷 111-116页

作者： Xinxin Guo Zhongwei Chen Ke Feng Siyao Zeng junfei Zhang Zhe Ma Changda yuan School of Clinical Medicine Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina Emergency Department General Hospital of Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina

Background:This study aims to explore the significance of serum amylase levels in patients with organophosphorus pesticide(OP)poisoning and to provide a new perspective for evaluating the severity and prognosis of OP ***:The clinical data of 67 patients with acute OP poisoning,who had been treated in the emergency department of the General Hospital of Ningxia Medical University between September 2020 and August 2022,were retrospectively *** Spearman rank correlation,serum amylase levels during admission and severity of poisoning correlated with discharge *** on serum amylase levels,receiver operating characteristic curves were plotted to predict the severity and mortality of patients who experience organophosphate *** optimal threshold serum amylase level at admission was determined based on the maximum Youden ***:Using Spearman rank correlation analysis,serum amylase levels at admission positively correlated with the severity of poisoning and discharge outcomes,but the degree of correlation was weak(r_(s):0.344;0.264;P194.1 U/L at admission was 15.944(95%CI:1.825-139.274).Conclusion:Serum amylase levels in patients with organophosphate poisoning correlate with the degree of poisoning and discharge *** serum amylase level was a risk factor for organophosphorus poisoning death.

关键词： Amylase Emergency department Organophosphorus pesticide poisoning Prognosis

均流腔结构对微细通道内相变流动特性影响的实验研究

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化工学报 2023年第S1期74卷 235-244页

作者：江河袁俊飞王林邢谷雨河南科技大学建筑能源与热科学技术研究所河南洛阳471023

以R134a制冷剂为工质,在质量流率为416~728 kg/(m^(2)·s),基面热通量为36.7~242.6 kW/m^(2)条件下,研究了方形均流腔和圆弧均流腔微细通道换热器内两相流型的变化规律以及不同条件下微通道的压降特性、压力波动特性与传热特性。结果表... 详细信息

以R134a制冷剂为工质,在质量流率为416~728 kg/(m^(2)·s),基面热通量为36.7~242.6 kW/m^(2)条件下,研究了方形均流腔和圆弧均流腔微细通道换热器内两相流型的变化规律以及不同条件下微通道的压降特性、压力波动特性与传热特性。结果表明:两种均流腔结构的微通道内流型过渡是相似的,在弹状流型时均观察到了流动逆转现象;相比于方形均流腔微通道,圆弧均流腔微通道的压降更低,压力波动幅度更小,且具有更高的传热系数。在热通量为242.6 kW/m^(2),质量流率为416 kg/(m^(2)·s)条件下,压降降低了51%;在热通量为154.4 kW/m^(2),质量流率为416 kg/(m^(2)·s)时,出口压力波动幅度降低了35%;当热通量为242.6 kW/m^(2),质量流率为728 kg/(m^(2)·s)时,微细流道末端的传热系数提高了9.7%。

关键词：微通道相变气液两相流压降不稳定性

入口流速对间断微通道内流型演变及流量分配特性影响

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过程工程学报 2023年第1期23卷 57-66页

作者：袁鑫森袁俊飞王林江河曹艺飞河南科技大学建筑能源与热科学技术研究所河南洛阳471023

微通道内气液两相流动规律是影响微通道换热器换热系数和流场温度均匀性的主要因素。以N2和H2O为工质,对间断、并联矩形微通道换热器内气液两相流型的起始、发展、稳定过程的演化以及并联通道内流量分配不均匀特性进行了数值模拟研究。... 详细信息

微通道内气液两相流动规律是影响微通道换热器换热系数和流场温度均匀性的主要因素。以N2和H2O为工质,对间断、并联矩形微通道换热器内气液两相流型的起始、发展、稳定过程的演化以及并联通道内流量分配不均匀特性进行了数值模拟研究。结果表明,不同的进口Re对微通道内流型的演变过程和流动周期有重要影响,当进口Re为450时,气相工质在均流腔内以离散的散团状形态脉动扩散至微通道中,并联通道内气相工质从弹状流型态逐渐转变为泡状流型态;当进口Re增至为1600时,气相工质在均流腔内以较连续的椭圆状型态扩散至微通道中,并联通道内气相工质从环状流型态逐渐转变为泡状流型态。通道结构还将影响并联通道间的流量分配的均匀性,间断微腔的存在使微通道内工质质量流量分布均匀性提升38.7%,通过研究通道内压力分布规律,发现通道内静压的分布不均匀是导致两相工质从均流腔进入微通道时发生不均匀分配的重要原因。

关键词：间断微通道两相流入口流速流型演变流量分配

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高功率储能相变冷却系统实验研究

制冷学报 2020年第1期41卷 124-130页

作者：袁俊飞王林谈莹莹焦永刚河南科技大学制冷热泵空调技术研究所洛阳471023 石家庄铁道大学机械工程学院石家庄050043

本文针对间歇工作的高功率电子设备对冷却系统的特殊需求,研制了一种以蒸气压缩制冷循环为基础的复叠式储能相变冷却系统,理论分析了系统的工作原理和工质选择原则,模拟计算了储能器的运行特性,通过实验测量了系统启动和稳定运行时的冷... 详细信息

本文针对间歇工作的高功率电子设备对冷却系统的特殊需求,研制了一种以蒸气压缩制冷循环为基础的复叠式储能相变冷却系统,理论分析了系统的工作原理和工质选择原则,模拟计算了储能器的运行特性,通过实验测量了系统启动和稳定运行时的冷却能力和运行性能。结果表明:机械泵启动时,系统压力先降低后升高,幅值为30 kPa,热源启动时,系统压力先升高后降低并维持稳定,系统的主要压降发生在冷却器中;储液器在热源启动时,能有效储存系统多余的工质,并间接控制冷却器内的相变温度和压力;储能器在系统运行过程中,满足系统换热需求并维持机械泵入口5℃的过冷度,设计合理;系统的冷却能力随运行时间逐渐降低,当平均热负荷超过10 kW时,系统能稳定运行5 min,满足课题的设计要求。

关键词：制冷系统相变储能热负荷

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相变储能冷却系统中储液器的设计与实验研究

过程工程学报 2020年第12期20卷 1439-1447页

作者：袁俊飞王林王占伟焦永刚河南科技大学制冷热泵空调技术研究所河南洛阳471023 石家庄铁道大学四方学院机械工程学院河北石家庄050043

相变储能冷却系统是用于短时大功率电子设备热管理的重要技术,系统在工作过程中的温度压力控制是该系统在应用过程中急需解决的问题。以NH3为制冷工质,针对10 kW热源的储能冷却系统中储液器进行理论分析和设计计算,建立相应的实验台,测... 详细信息

相变储能冷却系统是用于短时大功率电子设备热管理的重要技术,系统在工作过程中的温度压力控制是该系统在应用过程中急需解决的问题。以NH3为制冷工质,针对10 kW热源的储能冷却系统中储液器进行理论分析和设计计算,建立相应的实验台,测试其运行特性。结果表明,储液器作为该系统的定压设备,在动力设备和热源启动及运行过程中,对系统循环工质起到补充和存储作用。储液器的压力波动随热源功率的增加而增大,随储液器和管路容积比的增大而减小。当储液器和管路系统的容积比为1.48时,热源运行期间温度波动仅为1.2℃。在热源受到扰动时,储液器和储能器的耦合工作特性能有效抑制系统的温度压力波动。

关键词：冷却系统储液器相变稳定性

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太阳能辅助的双源耦合热泵系统制热特性研究

太阳能学报 2019年第8期40卷 2272-2278页

作者：王林付文轩谈莹莹梁坤峰袁俊飞河南科技大学制冷热泵空调技术研究所

传统空气源热泵在较低环境温度下存在制热量不足和制热效率偏低问题,该文提出一种太阳能辅助的双源双压缩耦合热泵系统,通过集热器将太阳能转化为低温热水以构建太阳能水源热泵单元,利用2台压缩机和1台冷凝器实现太阳能水源热泵单元和... 详细信息

传统空气源热泵在较低环境温度下存在制热量不足和制热效率偏低问题,该文提出一种太阳能辅助的双源双压缩耦合热泵系统,通过集热器将太阳能转化为低温热水以构建太阳能水源热泵单元,利用2台压缩机和1台冷凝器实现太阳能水源热泵单元和空气源热泵单元并联耦合工作。太阳能水源热泵单元和空气源热泵单元既能各自独立运行又能同时运行以满足用户全天候热负荷需求。基于DeST软件评估一个供热期(120 d)郑州某建筑逐时热负荷特性。在建立热力学数学模型基础上编写程序进行新系统循环特性计算和能耗分析,结果表明:双源耦合热泵系统COP_h较传统空气源热泵明显升高;前者日节能率介于1.01%~14.75%之间,在整个供热期总能耗较后者减少8.72%。双源(空气源蒸发器和水源蒸发器)双压缩机并联流程耦合热泵比双源单压缩机串联流程耦合热泵更具有节能优势。

关键词：空气源热泵节能蒸发器制热性能系数(COP_h) 双源耦合