A study on the multi-field synergy principle of convective heat and mass transfer enhancement

Liu, W.; Liu, Peng; Dong, Zhimin; Yang, Kun; Liu, Z.C.

doi:10.1016/j.ijheatmasstransfer.2019.01.077

Cited by 73 publications

(11 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The angle between the temperature gradient and velocity reflects heat transfer performance, while that between pressure gradient and velocity reflects flow resistance [7,8]. An experiment based on field synergy was carried out to analyze the thermal and flow characteristics in a circular tube [9]. Furthermore, exergy destruction was treated as a criterion to optimize the heat transfer activities [10].…”

Section: Introductionmentioning

confidence: 99%

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

Dong¹,

Du²

2021

Coatings

View full text Add to dashboard Cite

The process of heat exchange between two fluids of different temperatures and separated by a solid wall occurs in many engineering applications. Log mean temperature difference and effectiveness-NTU methods are widely used to assist in the design of heat exchangers. However, the two methods focus on overall analysis and cannot show the local temperature distributions. This paper obtains the mathematical solutions to the temperature profiles in an ideal counterflow heat exchanger. The aim of this research is to explain the phenomenon called the “entropy generation paradox”, which indicates a discrepancy between effectiveness and optimal entropy generation. The theoretical analysis reveals that the temperature curves are exponential functions when the heat capacity rates of the two streams are different; otherwise, the curves are linear functions. A heat exchanger is demonstrated to draw the temperature profiles under different working conditions. Local entropy generation rates are determined by the ratio of local stream temperatures in the form of a hook function. To realize a certain heat duty, there are many stream flow rate couples, and each couple results in a different entropy generation profile and obtains a corresponding total entropy generation. The helical steam generator of a high-temperature gas-cooled reactor is analyzed in this article and the principle of equipartition of entropy generation is confirmed. This principle indicates that, among the many working conditions to achieve a certain heat duty, a heat exchanger characterized by a nearly constant entropy production gives the best second law efficiency possible in order to achieve the best energy conversion.

show abstract

Section: Introductionmentioning

confidence: 99%

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

Dong¹,

Du²

2021

Coatings

View full text Add to dashboard Cite

show abstract

“…Subsequently, Tao et al [31][32][33] performed many numerical researches on the field synergy principle. Furthermore, to reduce power consumption of the fluid, Liu et al [34][35][36][37] proposed the multi-field synergy principle and optimized convective heat transfer with variation method in the tube. In addition, Chen et al [38,39] also optimized convective heat transfer with variation method.…”

Section: Introductionmentioning

confidence: 99%

A Solution to Pressure Equation with Its Boundary Condition of Combining Tangential and Normal Pressure Relations

Xiao¹,

Liu²

2021

Energies

View full text Add to dashboard Cite

Pressure is a physical quantity that is indispensable in the study of transport phenomena. Previous studies put forward a pressure constitutive law and constructed a partial differential equation on pressure to study the convection with or without heat and mass transfer. In this paper, a numerical algorithm was proposed to solve this pressure equation by coupling with the Navier-Stokes equation. To match the pressure equation, a method of dealing with pressure boundary condition was presented by combining the tangential and normal direction pressure relations, which should be updated dynamically in the iteration process. Then, a solution to this pressure equation was obtained to bridge the gap between the mathematical model and a practical numerical algorithm. Through numerical verification in a circular tube, it is found that the proposed boundary conditions are applicable. The results demonstrate that the present pressure equation well describes the transport characteristics of the fluid.

show abstract

“…In order to better understand the nature of the convective heat transfer, Guo el al. [32,33] proposed the field synergy principle, then further developed by Liu et al [34,35], to guide the design of convective heat trnsfer process with higher heat transfer efficiency and lower flow resistance. With the development of the computation techonology, there are a tendency to design heat transfer unit or system based on the combination of the CFD and optimization algorithm [36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Heat Transfer Performance in Packed Bed

Wang

Liu

et al. 2019

Energies

View full text Add to dashboard Cite

Packed beds are widely used in industries and it is of great significance to enhance the heat transfer between gas and solid states inside the bed. In this paper, numerical simulation method is adopted to investigate the heat transfer principle in the bed at particle scale, and to develop the direct enhanced heat transfer methods in packed beds. The gas is treated as continuous phase and solved by Computational Fluid Dynamics (CFD), while the particles are treated as discrete phase and solved by the Discrete Element Method (DEM); taking entransy dissipation to evaluate the heat transfer process. Considering the overall performance and entransy dissipation, the results show that, compared with the uniform particle size distribution, radial distribution of multiparticle size can effectively improve the heat transfer performance because it optimizes the velocity and temperature field, reduces the equivalent thermal resistance of convection heat transfer process, and the temperature of outlet gas increases significantly, which indicates the heat quality of the gas has been greatly improved. The increase in distribution thickness obviously enhances heat transfer performance without reducing the equivalent thermal resistance in the bed. The result is of great importance for guiding practical engineering applications.

show abstract

A study on the multi-field synergy principle of convective heat and mass transfer enhancement

Cited by 73 publications

References 32 publications

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

A Solution to Pressure Equation with Its Boundary Condition of Combining Tangential and Normal Pressure Relations

Numerical Study on Heat Transfer Performance in Packed Bed

Contact Info

Product

Resources

About