Numerical study of heat transfer enhancement in the receiver tube of direct steam generation with parabolic trough by inserting metal foams

Wang, P.; Liu, D.Y.; Xu, Chunxiao

doi:10.1016/j.apenergy.2012.07.026

Cited by 225 publications

(61 citation statements)

References 24 publications

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“…Therefore, reducing these temperature gradients and temperature peaks can go a long way in increasing the life span of the receiver and avoiding the thermal loss due to vacuum loss and hydrogen permeation in receiver's annulus space. The maximum temperature gradient for safe operation of receiver tubes is about 50 K [21] Enhancement of convective heat transfer in the receiver's absorber tube is one of the relevant solutions to the above concerns. With improved convective heat transfer in the absorber tube, circumferential temperature gradients and peak temperatures in the absorber tube can be reduced and risks of breakage and hydrogen formation can be minimised.…”

Section: Introductionmentioning

confidence: 99%

“…The wall temperatures and thermal loss were found to decrease with each geometrical parameter considered. Wang et al [21] investigated heat transfer enhancement using metal foams in a parabolic trough receiver for direct steam generation using realistic non-uniform heat flux boundary condition. They showed a maximum circumferential temperature difference was shown to reduce by 45%.…”

Section: Introductionmentioning

confidence: 99%

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Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts

2014

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In this paper, a numerical investigation of thermal and thermodynamic performance of a receiver for a parabolic trough solar collector with perforated plate inserts is presented. The analysis was carried out for different perforated plate geometrical parameters including dimensionless plate orientation angle, the dimensionless plate spacing, and the dimensionless plate diameter. The Reynolds number varies in the range 1.02×10 4 ≤ Re ≤ 7.38 × 10 5 depending on the heat transfer fluid temperature. The fluid temperatures used are 400 K, 500 K, 600 K and 650 K. The porosity of the plate was fixed at 0.65. The study shows that, for a given value of insert orientation, insert spacing and insert size, there is a range of Reynolds numbers for which the thermal performance of the receiver improves with the use of perforated plate inserts. In this range, the modified thermal efficiency increases between 1.2 -8 %. The thermodynamic performance of the receiver due to inclusion of perforated plate inserts is shown to improve for flow rates lower than 0.01205 m 3 /s. Receiver temperature gradients are shown to reduce with the use of inserts. Correlations for Nusselt number and friction factor were also derived and presented.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts

2014

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“…The approach is the following: a 1D two-phase flow model for the in-tube two-phase flow is coupled to a 3D heat transfer model of the receiver cavity, providing a simplified but accurate and computationally efficient model. A similar approach has been used by Zapata et al [48], one of the view reported modeling studies for solar-driven steam generation [46,48,49]. They used a 3D multi-mode heat transfer receiver model, however, they solved only a homogenous two-phase 1D model inside the absorber tube utilizing empirical correlations to predict the heat transfer between the tube surface and the working fluid without resolving the circumferential variations in the heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

Modeling and design guidelines for direct steam generation solar receivers

et al. 2018

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• A computational model for solar receiver for direct steam generation is developed.• Experiments are conducted and used to validate the model.• Practical designs, operational conditions and material choices are investigated.• Model provides design tool for direct steam generation solar cavity receivers. A R T I C L E I N F OKeyword: Solar energy Multi-mode heat transfer modeling Two-phase flow modeling Solar receiver Steam generator Concentrated solar A B S T R A C T Concentrated solar energy is an ideal energy source for high-temperature energy conversion processes such as concentrated solar power generation, solar thermochemical fuel production, and solar driven high-temperature electrolysis. Indirectly irradiated solar receiver designs utilizing tubular absorbers enclosed by a cavity are possible candidates for direct steam generation, allowing for design flexibility and high efficiency. We developed a coupled heat and mass transfer model of cavity receivers with tubular absorbers to guide the design of solardriven direct steam generation. The numerical model consisted of a detailed 1D two-phase flow model of the absorber tubes coupled to a 3D heat transfer model of the cavity receiver. The absorber tube model simulated the flow boiling phenomena inside the tubes by solving 1D continuity, momentum, and energy conservation equations based on a control volume formulation. The Thome-El Hajal flow pattern maps were used to predict liquid-gas distributions in the tubular cross-sections, and heat transfer coefficients and pressure drop along the tubes. The heat transfer coefficient and fluid temperature of the absorber tubes' inner surfaces were then extrapolated to the circumferential of the tube and used in the 3D cavity receiver model. The 3D steady state model of the cavity receiver coupled radiative, convective, and conductive heat transfer. The complete model was validated with experimental data and used to analyze different receiver types and designs made of different materials and exposed to various operational conditions. The proposed numerical model and the obtained results provide an engineering design tool for cavity receivers with tubular absorbers (in terms of tube shapes, tube diameter, and water-cooled front), support the choice of best-performant operation (in terms of radiative flux, mass flow rate, and pressure), and aid in the choice of the component materials. The model allows for an indepth understanding of the coupled heat and mass transfer in the solar receiver for direct steam generation and can be exploited to quantify the optimization potential of such solar receivers.

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“…Using the thermal performance index criterion, they selected the dimpled tube as the best case and they found 0.8% thermal efficiency enhancement with this technology. Wang et al [30] examined the use of metal foams in PTCs for steam generation. They proved that the Nusselt number can be about eight times greater than the empty tube, while huge pressure losses are found.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the thermal enhancement methods in parabolic trough collectors

Bellos

Tzivanidis

2017

Int J Energy Environ Eng

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Parabolic trough collector is an emerging solar technology for achieving the sustainability. Numerous studies have been focused on their performance evaluation and many techniques have been suggested for improving their thermal efficiency. The objective of this paper is to determine the impact of various thermal enhancement techniques on the thermal efficiency improvement of the PTC. The most usual techniques for increasing the thermal performance of parabolic trough collectors are the use of inserts, internal fins, metallic foams and the dimpled absorbers. A parametric analysis is conducted using different values of the thermal enhancement ratio (Nusselt number to the Nusselt number of the smooth absorber case). According to the final results, the thermal efficiency enhancement can reach up to 2% when the Nusselt number is about 2.5 times greater compared to the reference case and the inlet temperature is equal to 600 K. Moreover, in this case, the thermal losses are approximately 22% lower than in the respective reference case. For higher Nusselt number ratios, the thermal enhancement presents relatively small increase. This analysis is performed with a developed thermal model in Engineering Equation Solver (EES) which is validated with the literature results.

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Numerical study of heat transfer enhancement in the receiver tube of direct steam generation with parabolic trough by inserting metal foams

Cited by 225 publications

References 24 publications

Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts

Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts

Modeling and design guidelines for direct steam generation solar receivers

Assessment of the thermal enhancement methods in parabolic trough collectors

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