5 results on '"Dou, Binlin"'
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2. An experimental investigation of forced convection heat transfer with novel microencapsulated phase change material slurries in a circular tube under constant heat flux.
- Author
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Zhang, Guanhua, Cui, Guomin, Dou, Binlin, Wang, Zilong, and Goula, Maria A.
- Subjects
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FORCED convection , *HEAT transfer , *MICROENCAPSULATION , *PHASE change materials , *SLURRY , *HEAT flux - Abstract
This paper proposes novel microencapsulated phase change material slurries (MPCSs) as both the energy storage media and heat transfer fluids. The flow and heat transfer characteristics of MPCSs have been experimentally investigated. A series of experiments were conducted in laminar, transition and turbulent flow conditions for MPCSs in a circular tube under constant heat flux, respectively. The results of pressure drop measurements showed that transportation costs of slurries were close to pure water. The heat transfer experiments demonstrated that proposed MPCSs could enhance the heat transfer performance as the heat transfer fluids for thermal system applications in comparison with pure water. The average enhancement percentages of the Nusselt number were 23.9%, 20.5% and 9.1% for MPCS of 5 wt%, and enhancement of the Nusselt number was achieved when phase change material in the microcapsules were in solid, solid/liquid and liquid states, respectively. However, heat transfer enhancement of MPCS depends on the following combination factors: the slurry concentration, the flow rate, the pumping power and the heating rate. Importantly, the phase change process must be carefully controlled in the heat transfer test section with above combination factors in order to take advantages of MPCS over pure water. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
3. Effect of metal oxide particles on the flow and forced convective heat transfer behaviour of microencapsulated PCM slurry.
- Author
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Zhang, Guanhua, Zhang, Bin, Guo, Yuqian, Cui, Guomin, Dou, Binlin, Wang, Zilong, and Yan, Xiaoyu
- Subjects
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SLURRY , *HEAT convection , *METALLIC oxides , *GRANULAR flow , *HEAT transfer coefficient , *CONVECTIVE flow , *FORCED convection , *RHEOLOGY - Abstract
• The addition of metal oxide particles greatly improves the thermal conductivity of MPCS. • MPCS with metal oxide particles can enhance heat transfer under different flow conditions. • Heating power and flow rates are crucial to the heat transfer of MPCS. • MPCS with metal oxide particles can be used as heat transfer medium and energy storage fluid. ZnO, nano ZnO and nano Al 2 O 3 were mixed with microencapsulated phase change material slurry (MPCS) for improving the heat transfer performance of slurries in this paper. The thermal and rheological properties of MPCS were measured using DSC, thermal conductivity meter and rheometer. The results show that the thermal conductivity of 5 wt% MPCS with 1 wt% ZnO, nano ZnO and nano Al 2 O 3 was 17.9 %, 19.4 % and 23.5 % higher than that of 5 wt% MPCS, respectively. The forced convection heat transfer experiment of slurries was carried out in a loop system with various heat flux and flow conditions. The influences of heat flux, flow rate and metal oxide particles on the flow and heat transfer behaviour of slurries were investigated. The results show that the heat transfer was significantly enhanced for all slurries with metal oxide particles under three flow conditions. Compared with water, the local heat transfer coefficient (h x) of MPCSs with 1 wt% ZnO, nano ZnO and nano Al 2 O 3 increased by 6.5 %, 9.1 % and 12.4 % under laminar flow, 6.6 %, 15.5 % and 14.9 % under transition flow, and 15.7 %, 19.0 % and 21.6 % in turbulent condition, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Flow and heat transfer characteristics of microencapsulated phase change material slurry in bonded triangular tubes for thermal energy storage systems.
- Author
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Zhang, Guanhua, Wang, Mengke, Yan, Xiaoyu, Cui, Guomin, Dou, Binlin, Lu, Wei, and Yang, Qiguo
- Subjects
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HEAT storage , *NANOFLUIDICS , *PHASE change materials , *SLURRY , *ENERGY storage , *HEAT transfer , *HEAT convection , *HEAT transfer coefficient - Abstract
Three nanoscale metal oxides composed of nano TiO 2 , nano Al 2 O 3 , and nano MgO were added to the phase change microcapsule slurry for optimising the heat transfer behaviour. The thermal and rheological properties of the resulting microencapsulated phase change materials (MPCMs) and microencapsulated phase change material slurries (MPCSs) were characterized to determine the effects of added metal oxides in optimising the performance of MPCSs. The impacts of factors like metal oxides, concentrations, and flow rates on the heat transfer behaviour of MPCSs were investigated by forced convective heat transfer experiment with various working conditions. Compared to 6 wt% MPCSs, the heat transfer coefficients (h x) of 6 wt% slurries containing 1 wt% TiO 2 , 1 wt% Al 2 O 3 , and 1 wt% MgO increased by 4.0 %, 2.5 %, and 7.13 %, respectively. Nano-MgO showed the most significant heat transfer enhancement effect on MPCSs. Moreover, the heat transfer performance gradually enhanced as a function of the concentration for nano MgO. Overall, the addition of metal oxides enhanced heat transfer by increasing the thermal conductivity of the slurry, as well as improved the micro-convection effect. The proposed MPCSs are promising for applications in solar photovoltaic/thermal (PV/T) systems, chip cooling, thermal management, buildings, and automotive cooling. [Display omitted] • Forced convection heat transfer experiment were conducted with bonded triangular tubes. • Heat transfer enhancement achieved by optimising heat transfer medium and tube structure. • Metal oxide type and concentration have significant effect on heat transfer of slurries. • Nano-MgO showed the most significant heat transfer enhancement effect on slurries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Experimental investigation of the comprehensive heat transfer performance of PCMs filled with CMF in a heat storage device.
- Author
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Zhu, Mengshuai, Wang, Zilong, Zhang, Hua, Sun, Xiangxin, Dou, Binlin, Wu, Weidong, Zhang, Guanhua, and Jiang, Long
- Subjects
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HEAT storage devices , *HEAT transfer , *HEAT transfer coefficient , *NATURAL heat convection , *PARAFFIN wax , *HEAT storage - Abstract
• A greater proportion of copper metal foam (CMF) can enhance the heat transfer of paraffin wax and reduce the temperature gradient. • A theoretical model was built to calculate the comprehensive heat transfer coefficient of composite PCMs and to determine the intensity change of heat conduction and natural convection of PCMs with different CMF proportions. • Melting time and heat storage capacity of CMF composite PCMs first increased and then decreased with increasing CMF proportion. • Heat storage rate and comprehensive heat transfer coefficient first decreased and then increased with increasing CMF proportion. • Composite PCMs with a CMF proportion of 0.86% exhibit the best heat storage performance. Phase-change materials (PCMs) can overcome the low energy density and utilization efficiency of solar energy. However, the low thermal conductivity of PCMs significantly affects the thermal efficiency of solar devices; thus, improving the thermal conductivity of PCMs has been the focus of many recent studies. In this study, copper metal foam (CMF) composite PCMs were prepared using paraffin wax and high-pore-density CMF. The effect of the CMF proportion on heat transfer enhancement in the PCM melting process was analyzed using experimental equipment for heat storage visualization. Comprehensive heat transfer coefficients of CMF composite PCMs were obtained. The experimental results showed that as the CMF proportion increased from 0 to 2.15%, the melting time of the CMF composite PCMs and their heat storage capacity first increased and then decreased, whereas the heat storage rate and comprehensive heat transfer coefficient first decreased and then increased. The minimum temperature gradient of 8.09 K was reached when the CMF proportion was 2.15%. More importantly, as the proportion of CMF increased from 0.43 to 2.15%, the proportion of natural convection decreased from 87.90 to 17.69%, and natural convection was the major heat transfer mechanism in the melting process of composite PCMs with a low CMF proportion. The composite PCMs with a CMF proportion of 0.86% has the best heat storage performance when the heat storage capacity and heat storage rate were both considered. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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