Visualisation of heat transfer in 3D unsteady flows

Speetjens, Mfm Michel; Steenhoven, van Aa Anton

doi:10.1016/j.ijthermalsci.2010.01.012

Cited by 10 publications

(10 citation statements)

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“…This facilitates topological transport analyses by well-established methods from classical mechanics and has proven its worth in studies on (chaotic) mixing [4]. Recently, first generalisations of this ansatz to heat transfer have been undertaken [13,14,9]. Said studies concern locally-conservative mass and heat fluxes, i.e.…”

Section: Generic Composition Of the Thermal Topology In 2d Steady Sysmentioning

confidence: 99%

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A Lagrangian formalism for thermal analysis of laminar convective heat transfer

Speetjens

2012

J. Phys.: Conf. Ser.

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Heat transfer in essence is the transport of thermal energy along certain paths in a similar way as fluid motion is the transport of fluid parcels along fluid paths. This similarity admits Lagrangian heat-transfer analyses by the geometry of such "thermal paths" analogous to well-known Lagrangian mixing analyses. Essential to Lagrangian heat-transfer formalisms is the reference state for the convective flux. Existing approaches admit only uniform references. However, for convective heat transfer, a case of great practical relevance, the conductive state that sets in for vanishing fluid motion is the more natural reference. This typically is an inhomogeneous state and thus beyond the existing formalism. The present study closes this gap by its generalisation to non-uniform references and thus substantially strengthens Lagrangian methods for thermal analyses. This ansatz is demonstrated by way of a 2D case study and offers new fundamental insight into thermal transport that is complementary to the Eulerian picture based on temperature and heat-transfer coefficients.

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Section: Generic Composition Of the Thermal Topology In 2d Steady Sysmentioning

confidence: 99%

“…Fluid motion is according to the double-gyre flow u = [sin (2πx) cos (2πy) , − cos (2πx) sin (2πy)] and the sole system parameter is the Péclet number. Numerical methods are detailed in [14,9]. The flow topology coincides with the streamline portrait shown in Fig.…”

Section: An Illustrative Case Study: Convective Heat Transfer In 2d Smentioning

confidence: 99%

A Lagrangian formalism for thermal analysis of laminar convective heat transfer

Speetjens

2012

J. Phys.: Conf. Ser.

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“…Cryogenic ASU use the continuous process of stream compression, cooling, liquefaction and distillation. The cryogenic ASU mainly includes submachines which are air compressor (Label 2 in Fig.1), turbo expander (Labels 8,9), heat exchanger (Labels 11,12,14), distillation packing tower (Labels 13,15,16,17). The ASU process mainly contains adsorption subsystem, rectification subsystem and heat exchange subsystem.…”

Section: Cryogenic Air Separation Unit and The Heat Exchange Sub-systemmentioning

confidence: 99%

“…[15] modeled and simulated rectangular plain fin, strip offset fin, perforated fin, and wavy fin. Speetjens et al [16] studied visualisation of heat transfer in 3D unsteady flows.…”

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confidence: 99%

Thermal design of large plate-fin heat exchanger for cryogenic air separation unit based on multiple dynamic equilibriums

Chen

Zhang

et al. 2017

Applied Thermal Engineering

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Abstract：This paper presents a thermal design method of large plate-fin heat exchanger (PFHE) for cryogenic air separation unit (ASU) based on multiple dynamic equilibriums (MDE). The enlarging of PFHE brings cascading thermal design difficulties. Renault number of multi-streams in long passages fluctuates in wide range which generates various working conditions. The fin type of each passage and the Re for flowing streams are pre-set firstly. Using single-banking with top priority, the Recursive Prior Plug-In (RPP) method is proposed to complete permutation of hot streams and cold streams. The preferable passage arrangement is selected and determined according to the variance of the cumulative heat load. The initial temperature of each ordered stream in all the passages is then obtained. The temperature difference sequence between the one-sided adjacent streams is built. The large heat transfer area in plane perpendicular to the flowing direction is divided into MDE according to the temperature difference sequence. For each equilibrium, the heat balance equations between hot quantity and cold quantity are built by Fourier's law of heat conduction and heat convection. The final equilibrium temperature of each ordered stream in all the passages can be obtained by iterative solving the simultaneous differential equations for all MDE. Each long stream is also divided into MDE along flowing direction and modelled by energy conservation principle in enthalpy change to obtain the actual phase. The heat transfer process about Re is divided into MDE according to the dynamic equilibriums between heat transfer and frictional resistance to determine the optimal fins under different working conditions. The heat transfer experiment is completed to verify the proposed method. The MDE is applicable for various stacking patterns of numerous long hot streams and cold streams under variable working conditions. The proposed method is especially useful for thermal design of large energy-efficient PFHE for ASU.

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“…In literature these processes are analyzed in two groups: rapid thermal homogenization processes and heat transfer processes with high transfer rates in inhomogeneous directions [1]. Examples of thermal homogenization processes are the production of foods, polymers, steel and glass whereas heat treatment of certain polymers is an example for the latter class of processing.…”

Section: Introductionmentioning

confidence: 99%