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Your search keyword '"Zhang, Songyuan"' showing total 4 results
Start Over Author "Zhang, Songyuan" Topic nanofluid
4 results on '"Zhang, Songyuan"'

2. Characteristics of Flow Boiling Heat Transfer and Pressure Drop of MWCNT–R123 Nanorefrigerant: Experimental Investigations and Correlations

Author

Ge Zhong, Wang Huitao, Hua Wang, and Zhang Songyuan

Subjects
Mass flux, Pressure drop, Materials science, 020209 energy, Thermodynamics, 02 engineering and technology, Heat transfer coefficient, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Nanofluid, 020401 chemical engineering, Mechanics of Materials, Heat transfer, Vapor quality, 0202 electrical engineering, electronic engineering, information engineering, Particle, General Materials Science, 0204 chemical engineering, Nucleate boiling
Abstract

In the present work, the flow boiling heat transfer characteristics and pressure drop are experimentally investigated using multiwalled carbon nanotube (MWCNT)–R123-based nanofluids flowing inside a horizontal circular tube. The effects of particle concentration, mass flux, and vapor quality on the heat transfer coefficient (HTC) and pressure drop of MWCNT–R123-based nanofluid are analyzed. Results show that flow boiling HTC and frictional pressure drop increased with nanoparticle concentration, mass flux, and vapor quality as expected. The effects of nanoparticles on the flow boiling HTC and pressure drop are quantitatively analyzed by introducing a nanoparticle impact factor. A modified correlation for predicting the flow boiling HTC of nanorefrigerants is proposed, and the proposed correlation predicts 95% of the points with a deviation of ±20%. In addition, frictional pressure drop can be predicted using the Muller-Steinhagen and Heck correlation with a mean absolute error of 13.07% if the the...

Published
2016

3. A new semi-analytical model for effective thermal conductivity of nanofluids

Author

Hua Wang, Ge Zhong, Wang Huitao, and Zhang Songyuan

Subjects
Convection, Chemistry, 020209 energy, Thermodynamics, Nanoparticle, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Physics::Fluid Dynamics, Particle aggregation, Nanofluid, Thermal conductivity, Volume fraction, 0202 electrical engineering, electronic engineering, information engineering, Materials Chemistry, Particle size, Physical and Theoretical Chemistry, 0210 nano-technology, Brownian motion
Abstract

A new theoretical model for thermal conductivity of nanofluids is developed incorporating effective medium theory, interfacial layer, particle aggregation and Brownian motion-induced convection from multiple nanoparticles/aggregates. The predicated result using aggregate size, which represents the particle size in the actual condition of nanofluids, fits well with the experimental data for water-, R113- and ethylene glycol (EG)-based nanofluids. The present model also gives much better predictions compared to the existing models. A parametric analysis, particularly particle aggregation, is conducted to investigate the dependence of effective thermal conductivity of nanofluids on the properties of nanoparticles and fluid. Aggregation is the main factor responsible for thermal conductivity enhancement. The dynamic contribution of Brownian motion on thermal conductivity enhancement is surpassed by that of static mechanisms, particularly at high volume fraction. Predication also indicated that the vis...

Published
2016

4. Thermo-economic analysis of organic Rankine cycle using a new two-stage solar collector with nanofluids.

Author

Ge, Zhong, Xiang, Qingyun, Li, Jian, Zhang, Songyuan, Wang, Zhe, Xie, Jianbin, Xie, Zhiyong, and Yang, Fubin

Subjects
*PARABOLIC troughs, *SOLAR collectors, *NANOFLUIDS, *RANKINE cycle, *HEAT transfer fluids, *ALUMINUM oxide, *SOLAR energy
Abstract

• New two-stage collector coupling flat plate and parabolic trough types is designed. • Four nanofluids are added to enhance heat transfer performance of solar collector. • Cost reductions of two-stage collector are evaluated in organic Rankine cycles. • Unit cost of two-stage collector is 6.8% lower than parabolic trough collector. • Cu-oil nanofluid has the best heat transfer performance. The flat plate collector (FPC) has a low economic cost, while the parabolic trough collector (PTC) has a high heat collection temperature. To reduce costs, improve efficiency, and promote the use of solar energy, this study proposes a new two-stage solar collector that couples FPC and PTC. The main objective of this paper is to verify the performance of this two-stage solar collector when containing nanofluids. This collector drives the organic Rankine cycle (ORC) with four nanoparticles (Cu, CuO, TiO 2 , and Al 2 O 3) in the oil heat transfer fluid. The FPC outlet temperature in the two-stage solar collector is optimized, the exergy of ORC is analyzed, and the economics of the new system using nanofluid are calculated and compared with those of the new system without nanofluid. Results show that Cu-oil outperforms the other nanofluids in terms of heat transfer. At a rated output power of 5 kW, the new two-stage solar collector with 5 % Cu-oil can reduce economic costs by 6.8 % compared with a single PTC. Meanwhile, the ORC with a two-stage solar collector using 5 % Cu-oil reduces the economic costs by 5.7 % compared with the ORC equipped with PTC without nanofluid. The new system has a minimum payback period of 17.3 years, and increasing the output power of the ORC is beneficial for reducing the investment payback period of the system. [ABSTRACT FROM AUTHOR]

Published
2024
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