检索结果-内蒙古大学图书馆

Experimental Investigation on heating Performance of Newly Designed Air Source heat Pump System for Electric Vehicles

引用

JOURNAL OF THERMAL SCIENCE AND engineering APPLICATIONS 2021年第2期13卷 021020页

作者： Li, Kang Yu, Jun Yu, Rong Su, Lin Fang, Yidong Yang, Zhongcheng Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Key Lab Multiphase Flow & Heat Transfer Shanghai Shanghai 200093 Peoples R China

Utilizing the heat from air source with heat pump system in electric vehicles shows a significant advantage from thermoelectric heat source for heat supply in cold climate. It could improve the driving range of electric vehicles considerably in winter and replace the positive temperature coefficient (PTC) heater with an acceptable cost and reliability. In this work, a newly designed heat pump system was first introduced with less components and cost. Second, experiments were conducted to investigate its cooling performance, and subsequent heating performance from -10 to 10 degrees C. The typical heat transfer and flow characteristics of refrigerant were recorded, and the behavior of each component including compressor, evaporator, condenser, and outside heat exchanger were analyzed and interpreted. The results showed that the heating and cooling performance of the new heat pump system could almost remain the same with traditional air-conditioning system in automobile and surely satisfy with the heat requirement of electric vehicles. In the heating mode, the maximum heating capacity increases by 13% at 400 m(3)/h air volume from 300 m(3)/h at the ambient temperature -10 degrees C, while the outlet air temperature decreases by 4-6%. In addition, using a heat pump system showed an increase in the driving range of electric vehicles by 25-31% as compared to PTC heaters.

关键词： air source heat pump driving range heat capacity electric vehicle energy efficiency energy systems thermal systems

来源：评论

学校读者我要写书评

暂无评论

A study of a low pressure ratio vapor injection scroll compressor for electric vehicles under low ambient conditions

引用

INTERNATIONAL JOURNAL OF REFRIGERATION 2021年 131卷 186-196页

作者： Zhang, Xinxin Su, Lin Li, Kang Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Key Lab Multiphase Flow & Heat Transfer Shanghai Shanghai 200093 Peoples R China

Vapor injection technology is a promising method to improve the performance of heat pump systems on electric vehicles. In this work, an experimental study on a low pressure ratio vapor injection scroll compressor was carried out under low ambient temperature conditions. Comparative experiments were conducted for various injection pressures, compressor speeds, and evaporation temperatures. The typical flow and heat transfer characteristics were obtained and analyzed, especially the compressor volumetric efficiency and compressor efficiency. The results showed that the heating performance was improved and discharge temperature was reduced with the increasing injection pressure at a higher compressor speed and a lower evaporation temperature. The volumetric efficiency and compressor efficiency both decreased with the increasing injection pressure. The maximum heating capacity could increase by 16% and the maximum discharge temperature reduction would reach 8 degrees C for the vapor injection process compared with non-injection process under the evaporation temperature of -22 degrees C. Furthermore, a semi-empirical model with correlations of volumetric efficiency and compressor efficiency was developed. The results were validated and showed a reasonable agreement with experimental results.

关键词： Electric vehicles Vapor injection scroll compressor Low pressure ratio compressor Compressor experimental study Compressor model

来源：评论

学校读者我要写书评

暂无评论

The effect of heat flux on enhancement heat transfer mechanism in copper metal foam composite paraffin wax during melting process: Experimental and simulation research

引用

INTERNATIONAL JOURNAL OF heat AND MASS transfer 2024年 226卷

作者： Wang, Zilong Gui, Jintao Zhu, Liucan Zhang, Hua Dou, Binlin Yu, Guoxin Song, Mengjie Jiang, Lianyong Xiao, Xin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China QINGDAO HAIER SMART TECHNOL R&D CO LTD 1 Haier Rd Qingdao Shandong Peoples R China Beijing Inst Technol Sch Mech Engn Dept Energy & Power Engn Beijing 100081 Peoples R China Shanghai Jiao Tong Univ Xinhua Hosp Sch Med Dept Cardiothorac Surg Shanghai 200092 Peoples R China Donghua Univ Coll Environm Sci & Engn Shanghai 201620 Peoples R China

To investigate the effect of heat flux on the enhanced heat transfer in phase change materials (PCMs) composed of copper metal foam (CMF) and paraffin wax (PX), a semi-cylindrical visualized heat storage device with a varied heat flux of 7.3 kW/m2, 8.5 kW/m2, 9.7 kW/m2, and 10.9 kW/m2 was established in this paper. Moreover, a 3-D mathematical model of composite phase change materials (CPCMs) was established using hybrid grid to study the temperature distribution, imbalance effect, flow, heat transfer mechanisms, and heat storage performance during the melting process. The results showed that the melting time of the CPCMs decreased as the heat flux increased. Compared with a heat flux of 7.3 kW/m2, the melting time was shortened by 10.05 %, 20.71 %, and 27.21 %, respectively. In addition, the Rayleigh number (Ra) increased with the increase in heat flux, and the amplitudes of Ra were 1.45x108,1.54x108,1.61x108, and 1.74x108, respectively, which indicated that the higher the heat flux, the larger the amplitudes. Moreover, the heat transfer mechanism during the melting process was dominated by conduction;however, with the increase in heat flux, the maximum flow velocity of the liquid paraffin increased, which caused the proportion of natural convection to increase from 27.80 % to 31.30 %. Hence, the integrated heat transfer coefficient of CPCMs increased from 5.69 W/(m & sdot;K) to 5.81 W/(m & sdot;K). However, the temperature imbalance effect of the CPCMs was exacerbated, as evidenced by the increased maximum temperature difference in the vertical direction of the center of the CPCMs from 24.7 K to 35.6 K. Besides, the heat storage performance was enhanced. Compared with a heat flux of 7.3 kW/m2, the heat storage capacities of the CPCMs increased by 4.21%, 9.46%, and 12.66 % with increasing heat flux, and the heat storage rates of the CPCMs increased by 15.3 %, 34.9 %, and 52.3 %, respectively. Furthermore, the relative error of the overall melting time was 3.4 %, in

关键词： heat flux Phase change materials Copper metal foam Numerical simulation heat transfer mechanism

来源：评论

学校读者我要写书评

暂无评论

An polymorphic firefly algorithm with self-adaptation strategy for process system heat integration

引用

CASE STUDIES IN THERMAL engineering 2023年 47卷

作者： Chen, Jiaxing Cui, Guomin Shen, Shuqi Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

Parameter setting effecting on solving efficiency is problematic and challenge of heuristic algorithm in engineering optimization. To reinforce the algorithm optimization, self-adaptation strategy of optical absorption coefficient based on dynamical spatial distribution of individual information is provided for parameter adjustment of Polymorphic firefly algorithm. This method is utilized to test and calculate three different scale heat exchanger network examples in public literature. More economic networks of lower total annualized cost are obtained, and the three cases are all calculated in about 1 h, which shows the higher convergence efficiency of this method.

关键词： Polymorphic firefly algorithm Self-adaptation strategy Process system heat integration heat exchanger network synthesis

来源：评论

学校读者我要写书评

暂无评论

Biochar-assisted water electrolysis for energy-saving hydrogen production: Evolution of corn straw-based biochar structure and its enhanced effect on Cr(VI) removal

引用

ENERGY 2024年 305卷

作者： Ying, Zhi Du, Yueyue Gu, Xufei Yu, Xiaosha Zheng, Xiaoyuan Dou, Binlin Cui, Guomin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Pyneo Co Ltd Hangzhou 311000 Peoples R China

Biochar-assisted water electrolysis (BAWE) offers a novel strategy for clean hydrogen production and biochar utilization. Here we propose the production of activated biochar via limited biochar electrooxidation over Ni foam and its application to remove Cr(VI). The corn straw-based biochar oxidation reaction delivers 100 mA cm-2@1.528 V vs. RHE, and reaches 98 % Faradaic efficiency for H2 production. The electrical consumption of 4.16 kWh Nm- 3 H2 for BAWE is lower than 5.07 kWh Nm- 3 H2 for water electrolysis. After 10 h electrolysis at 5 mA cm-2, due to the direct oxidation of biochar at electrode and indirect oxidation by reactive oxygen species in solution, the activated biochar is formed with increased pore size and specific surface area, and full of -OH, C-O, C--O, and COOH groups. The removal rate of Cr(VI) by activated biochar reaches 72.79 %, much higher than the 10.96 % for original biochar, which is attributed to the well-developed mesoporous structure of activated biochar for Cr(VI) adsorption, and the enriched -OH and COOH for Cr(VI) reduction and Cr(III) complexation. These findings confirm the feasibility of electrochemical activation of biochar in BAWE process, which demonstrate a new avenue for biochar upgrading and energy-saving hydrogen production for a sustainable future.

关键词： Biochar-assisted water electrolysis (BAWE) Biochar Electrochemical activation Hydrogen Cr(VI) removal

来源：评论

学校读者我要写书评

暂无评论

Research on depth measurement calibration of light field camera based on Gaussian fitting

引用

SCIENTIFIC REPORTS 2024年第1期14卷 1-11页

作者： Yang, Miao Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

Optical field imaging technology does not require a complicated optical path layout and thus reduces hardware costs. Given that only one single exposure of a single camera can obtain three-dimensional information, this paper proposes an improved calibration method for depth measurement based on the theoretical model of optical field imaging. Specifically, the calibration time can be reduced since the Gaussian fitting can reduce the number of refocused images used to obtain the optimal refocusing coefficient calibration. Moreover, the proposed method achieves the same effect as the multiple refocusing calibration strategy but requires less image processing time during calibration. At the same time, this method's depth resolution is analyzed in detail.

关键词： Image rendering Gaussian fitting Depth calibration Depth resolution

来源：评论

学校读者我要写书评

暂无评论

Wetting States and Departure Diameters of Bubbles on Micro-/Nanostructured Surfaces

引用

LANGMUIR 2022年第10期38卷 3180-3188页

作者： Li, Junyang Gong, Shuai Zhang, Lenan Cheng, Ping Ma, Xiaojing Hong, Fangjun Shanghai Jiao Tong Univ Sch Mech Engn Shanghai 200240 Peoples R China MIT Dept Mech Engn Cambridge MA 02139 USA North China Elect Power Univ Beijing Key Lab Multiphase Flow & Heat Transfer L Beijing 102206 Peoples R China Suzhou Univ Sci & Technol Jiangsu Key Lab Micro & Nano Heat Fluid Flow Tech Suzhou 215009 Jiangsu Peoples R China

Wetting states for droplets have been extensively investigated in the past. As the counter phase of the droplets, bubbles' wetting states have rarely been systematically explored. The wetting state of a bubble is closely related to its departure diameter, which plays significant roles in bubble-generated processes in boiling heat transfer and gas-evolving reactions. Based on the principle of minimum surface energy, we explicitly define three equilibrium wetting states (hemi-wicking state, Wenzel state, and Cassie-Baxter state) for bubbles on micro-/nanostructured surfaces in this paper. We analyze the three-phase contact line profiles for bubbles under these wetting states and propose theoretical models for predicting departure diameters of hemi-wicking-state bubble and Wenzel-state bubble on micro-/nanostructured surfaces. We identify competing effects of bubble departure in Wenzel state: the augmentation of contact line length due to the roughness, which would delay bubble departure, and the decrease of contact line length due to the reduced apparent contact angle, which would facilitate bubble departure. We demonstrate that hemi-wicking-state bubble exhibits a much smaller departure diameter on the textured surfaces. These findings are supported by numerical simulations by the three-dimensional (3D) multiple-relaxation-time lattice Boltzmann method. It is found that the length of the outermost contact lines instead of all contact lines determines the departure diameter of hemi-wicking-state bubble based on bubble detachment processes captured by our 3D numerical simulations. This work offers an avenue for the accurate prediction and control of bubble departure behaviors from micro-/nanostructured surfaces, and therefore can guide optimal designs of micro-/nanostructured surfaces in a variety of applications in boiling, desalination, and hydrogen production by electrolysis.

关键词： Bubbles Contact angle Liquids Equilibrium Wetting

来源：评论

学校读者我要写书评

暂无评论

Design and Simulation of a New Type of Fin-and-Tube heat Exchanger with Trapezoidal Slit Fins

SSRN

引用

SSRN 2024年

作者： Zhang, Tianjiao Su, Mengyang Zhang, Hua Liu, Chuang Ouyang, Xinping School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China Key Laboratory of Thermo-Fluid Science and Engineering Ministry of Education Xi’an Jiaotong University Xi’an710049 China

Slit fin-and-tube heat exchangers are extensively utilized in industry, and optimizing the fin structure is conducive for improving energy efficiency and reducing energy losses. Therefore, a heat exchanger featuring trapezoidal slit fins was proposed in this study. To determine the structure of the slit fins, physical and mathematical models of the heat exchanger with a fin spacing Fp of 2.65 mm were established. We used a numerical simulation to investigate the structural parameters of the fin-and-tube heat exchanger, including the slit height Sh, slit width Sw, transverse tube spacing Pt, and longitudinal tube spacing Pl. Based on the simulation results, the effects of the four structural parameters on the comprehensive performance were evaluated. Additionally, the optimal parameter combination was determined through an orthogonal test, resulting in the following values: Sh = 1.47 mm, Sw = 4 mm, Pt = 42 mm, and Pl = 27.5 mm. This study provides significant theoretical and practical guidance. © 2024, The Authors. All rights reserved.

关键词： Energy dissipation

来源：评论

学校读者我要写书评

暂无评论

Unraveling Reactive Nitrogen Emissions in Heavy-Duty Diesel Vehicles across Evolving Standards and Cheating Tactics

引用

ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024年第52期58卷 23180-23189页

作者： Ding, Xiang Huang, Cheng Huang, Dan Dan Hou, Yong Hu, Qingyao Lou, Shengrong Wang, Meng Zhou, Min Chen, Jun Yang, Huinan Huang, Rujin Fu, Qingyan Wang, Hongli Shanghai Acad Environm Sci Key Lab Format & Prevent Urban Air Pollut Complex Minist Ecol & Environm Shanghai 200233 Peoples R China Shanghai Acad Environm Sci State Environm Protect Key Lab Format & Prevent Ur Shanghai 200233 Peoples R China Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Chinese Acad Sci Inst Earth Environm Ctr Excellence Quaternary Sci & Global Change State Key Lab Loess & Quaternary Geol Xian 710061 Peoples R China Shanghai Environm Monitoring Ctr State Ecol & Environm Sci Observat & Res Stn Yangt Shanghai 200030 Peoples R China

Reactive nitrogen (Nr) emissions significantly affect air quality and the nitrogen cycle in ecosystems. Heavy-duty diesel vehicles (HDDVs), as major sources of these emissions, exhibit complex emission characteristics because of the combined effects of different driving conditions and aftertreatment technologies. This study first investigated the emission factors (EFs) of Nr species, including NO, NO2, HONO, N2O, and NH3, from HDDVs under different emission standards (China IV/V/VI) and cheating strategies, with a particular focus on the impact of selective catalytic reduction (SCR) systems. Vehicles employing water injection cheating present NO, NO2, and HONO EFs that are consistent with the China III standards, significantly undermining the effectiveness of Nr emission control. The evolution of SCR technology in China IV, V, and VI standards has generally led to substantial reductions in NO, NO2, and HONO emissions, yet the integration of ammonia slip catalysts (ASC) systems in China VI vehicles presents new challenges. While ASCs have successfully reduced NH3 slip to an average of 17 +/- 12 mg/km, they have also caused a 6-13-fold increase in N2O emissions compared with those of China IV and V vehicles, reaching levels of 205 +/- 85 mg/km. Additionally, China VI vehicles exhibit a marked increase in the HONO/NOx ratio, which increases from 0.9% in China V to 4.6%. These increases are attributed to high-temperature oxidation of NH3 within the ASC catalyst, leading to undesirable byproducts. The temporal dynamics of Nr emissions under real-world driving conditions further reveal that the effectiveness of aftertreatment technologies and their selectivity toward byproducts vary depending on the driving mode. This variability underscores the need for further optimization of the SCR and ASC technologies to balance the control of all the reactive nitrogen species effectively.

关键词： reactive nitrogen HDDV HONO N2O emission factors

来源：评论

学校读者我要写书评

暂无评论

Large eddy simulation on the wake characteristics of linearly stratified flow past a sphere

引用

Scientific Reports 2025年第1期15卷 1-13页

作者： Xia, Tianci Wei, Na Shi, Liuliu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093 China Key Laboratory of Power Machinery and Engineering of Ministry of Education Shanghai Jiao Tong University Shanghai 200240 China

In this study, Large Eddy Simulation (LES) has been employed to examine the influence of the Froude number (Fr) on the linearly stratified wake and internal waves behind a sphere at a subcritical Reynolds number of Re = 3700. Six distinct sets of models with varying Fr (Fr = 0.05, 0.25, 0.5, 1, 2, ∞) have been chosen to establish density linear stratification through the use of a User Defined Function (UDF). The analysis focuses on the impact of stratification on wake characteristics, velocity distribution, and the structure of internal waves within stratified flow. It is evident that density stratification plays a pivotal role in shaping wake structure. Notably, in stratified flows, wakes exhibit unique characteristics including the generation of internal waves, suppression of vertical velocity, and the emergence of oscillating wake patterns. The study reveals that a decrease in the Froude number leads to heightened vertical suppression of the wake and increased anisotropy of the velocity distribution. Furthermore, as the Froude number ascends from 0.05 to 2, the wake undergoes a transition from quasi-two-dimensional vortex shedding to three-dimensional turbulence. © The Author(s) 2025.

关键词： Froude number Internal wave Linearly stratified flow Wake

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：