Enhanced Heat Transfer Efficiency Research Articles

Heat Transfer Enhancement Using Micro Porous Structured Surfaces

The parabolic trough solar collector as a popular technique is widely used in solar concentrating technologies (SCTs). The solar absorber tube is the key position of the trough solar thermal power system. The internal modification of the absorber tube is one of the most interesting techniques for increasing the collector’s performance. At present, most of the methods to enhance heat transfer efficiency focus on designing alternative parabolic trough collectors (PTC) absorbers and improving the internal structure of absorption tubes. Due to the limitation of temperature range, most absorption tubes use oil as heat absorbing liquid, and very few heat absorbing tubes directly use water as working fluid. This is because water is limited by critical heat flux in high temperature environment, resulting in low heat transfer performance. In this work, we designed a new porous absorber tube with the function of allowing liquid resupply and vapor overflow from different paths, which can effectively improve the critical heat flux of the absorber tube when using distilled water as working fluid. In order to obtain better heat transfer performance of the absorber and verify the feasibility of vapor–liquid separation mechanism, a simplified model of the absorber was carried out in pool boiling. In this work, we fabricated an arterial porous structure with the function of regulating vapor–liquid flow path based on vacuum sintering technique, and the effect of different heating methods on boiling heat transfer performance are analyzed. The maximum heat flux of 450 W/cm2 was achieved without any dry-out at the superheat of 42 °C, and the unique evaporation/boiling curve was obtained.

Thermal Waves and Heat Transfer Efficiency Enhancement in Harmonically Modulated Turbulent Thermal Convection

We study turbulent Rayleigh-Bénard convection over four decades of Rayleigh numbers 4×10^{8}<Ra<2×10^{12}, while harmonically modulating the temperatures of the plates of our cylindrical cell. We probe the flow by temperature sensors placed in the cell interior and embedded in the highly conducting copper plates and detect thermal waves propagating at modulation frequency in the bulk of the convective flow. We confirm the recent numerical prediction [Yang etal., Phys. Rev. Lett. 125, 154502 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.154502] of the significant enhancement of the Nusselt number and report its dependence on the frequency and amplitude of the temperature modulation of plates.

Experimental investigation on flow-induced vibrations of a circular cylinder with radial and longitudinal fins

Flow-induced vibration (FIV) of a heat exchanger tube may present both negative effects (e.g., causing fatigue damage of the tube) and positive effects (e.g., enhancing heat transfer efficiency). As a typical passive control approach, fins attached to the tube (or circular cylinder) present significant effects on its FIVs. This study carried out systematic wind tunnel tests to investigate the FIVs in the transverse direction (along with the drag forces) of a circular cylinder with various radial and longitudinal fins. For the radial group, 3 cases with spare, moderate, and dense fins were tested. For the longitudinal group, 24 cases with various fin numbers and arrangements were tested. For the longitudinal fin arrangement parallel to the flow direction (also known as a circular cylinder with single or dual splitter plates), various fin lengths were also tested. The experimental results showed that a radial finned cylinder always presents larger FIVs than a bare circular cylinder. The longitudinal fins may significantly increase or decrease the FIVs depending on the number and arrangement of attached fins. For example, a single splitter plate (placed either upstream or downstream of the circular cylinder) often increases the FIVs, while dual splitter plates with large lengths can effectively suppress the FIVs. The experimental results provide valuable guidance for selecting appropriate fin configurations to passively control the FIVs to a certain level that can enhance the heat transfer efficiency without introducing unacceptable fatigue damage.

Hybrid nanofluids flow and heat transfer in cavities: a technological review

ABSTRACT The urgent and indispensable need to develop new methods of enhancing heat transfer efficiency to improve energy devices’ performance cannot be overlooked in this era of green energy and sustainable technologies. Nanofluids research has proliferated in the past decade, and reports indicate that nanofluids can be used for heat transfer applications in engineering and in general and/or commercial industries. Nanofluid is the dispersion of nanoparticles with high thermal conductivity in common working fluids. Nevertheless, a growing area of research in recent years has involved using two or more nanoparticles in a base fluid, known as hybrid nanofluids. Studies show that hybrid nanofluids exhibited better thermal and rheological characteristics than mono nanofluids. In addition, many researchers have reported on the thermal-fluid behaviors of nanofluids in comparison with hybrid nanofluids on natural convection in cavity flows. This review discusses hybrid nanofluids preparation, stability analysis and characterization, thermal properties and heat transfer characteristics in cavities. Furthermore, hybrid nanofluids demonstrated better heat transfer characteristics than mono nanofluids or conventional fluids even if more research is needed in terms of hybrid nanofluids preparation, stability, characterization and applications.

Optimizing thermal efficiencies of power-law fluids in double-pass concentric circular heat exchangers with sinusoidal wall fluxes.

Effect of external-recycle operations on the heat-transfer efficiency, specifically for the power-law fluid flowing in double-pass concentric circular heat exchanger under sinusoidal wall fluxes, is investigated theoretically in the developed countries. Given that the fluid is heated twice on both sides of the impermeable sheet, four flow patterns proposed in recycling double-pass operations are expected to make substantial improvements in the performance of heat exchanger device in this study. Theoretical predictions point out that the heat-transfer efficiency increases with the ratio of channel thickness of double-pass concentric circular heat exchanger for all new designs under the same working dimension and the operational condition. The fluid velocity within the double-pass heat exchanger is increased by the fluids flowing through divided subchannels, which contributed to the higher convective heat-transfer efficiency. A simplified mathematical formulation was derived for double-pass concentric circular heat exchangers and would be a significant contribution to analyze heat transfer problems with sinusoidal wall fluxes at boundaries. The results deliver the optimal performance for the proposed four configurations with the use of external recycle compared to those conducted in single-pass, where an impermeable sheet is not inserted. The influences of power-law index and impermeable-sheet position on average Nusselt numbers under various flow patterns are also delineated. The distribution of dimensionless wall temperature was lower at the level of relative smaller thickness of annular channel, and the average Nusselt numbers for four external-recycle configurations and single-pass device were more suitable for operating under same condition. The ratio of the power consumption increment to heat-transfer efficiency enhancement demonstrates the economic feasibility among various configurations of double-pass concentric circular heat exchanger. The results also show that the external-recycle configuration (say Type B in the present study) serves as an important economic advantage in designing concentric circular heat exchangers for heating power-law fluids due to the smaller volumetric flow rate in annular channel with exiting outlet temperature.

Torsional vibration of a circular cylinder with an attached splitter plate in laminar flow

Splitter plates have been recognized as useful passive devices to reduce drag, mitigate flow-induced vibration, and enhance heat transfer efficiency of a circular cylinder. However, undesired torsional flow-induced vibrations due to splitter plate attachment require further investigation. This paper numerically studies the flow-induced torsional vibrations of an elastically mounted circular cylinder with an attached splitter plate in laminar flow with a Reynolds number of 100. A finite volume formulation is utilized to solve the incompressible two-dimensional fluid governing equations. Torsional vortex-induced vibrations (VIVs) are observed at lower reduced flow velocities, while a symmetry-breaking bifurcation occurs as the reduced flow velocity increases, after which the cylinder-plate assembly vibrates around a nonzero equilibrium angle. The numerical results show that the synchronization range of VIV extends, the peak VIV amplitude increases, and the critical reduced flow velocity for the bifurcation decreases with decreasing the moment of inertia. The symmetry-breaking bifurcation is due to a combined effect of the structural restoring moment and the flow-induced moment. The critical reduced velocity of the bifurcation and the nonzero equilibrium angle at any reduced velocity can be calculated based on the mean moment coefficients of the cylinder-plate assembly. The flow-induced moment is mainly induced by the pressure difference between the splitter plate's upper and lower surfaces. The phase difference between the torsional moment and displacement is 0° at lower reduced velocities, while the phase difference jumps to 180° at a reduced velocity of approximately 6.5. The mean drag coefficient of the vibrating cylinder-plate assembly is lower than the mean drag coefficient of a stationary circular cylinder but often higher than that of a stationary cylinder-plate assembly. The dominant frequency of the drag force is twice the vibration frequency before the symmetry-breaking bifurcation, while the dominant frequency becomes consistent with the vibration frequency after the bifurcation. The typical 2S mode of vortex shedding is identified for all considered moments of inertia and reduced flow velocities. However, the timing of a non-shedding vortex changes at the critical flow velocities for the phase jump and symmetry-breaking bifurcation. The observed torsional vibrations suggest that circular cylinders with splitter plate attachments may be competitive candidates for VIV-based energy harvesting, while they may not be good choices for heat exchangers.

Optimizing Thermal Efficiencies of Double-Pass Cross-Corrugated Solar Air Heaters on Various Configurations with External Recycling

The effect of external-recycle operations on the thermal performance of double-pass cross-corrugated solar air heaters (SAH) under different operating conditions was investigated experimentally and theoretically. Additionally, the simultaneous ordinary equations were solved analytically for each proposed configuration. Four recycling types are introduced for improving the solar thermal performance with different external recycle processes, which are expected to enhance the heat transfer coefficient with a convective turbulent flow between the air and the absorber in the present study. Using recycling double-pass operations, two processes were conducted sequentially: air first flowed over the sinusoidal corrugated absorber plate and then flowed back later over the transverse sinusoidal corrugated bottom plate. Improved device performance was achieved due to the doubled heat transfer area over and under the corrugated absorber plate, from which both the sinusoidal cross-corrugated absorber plate and bottom plate enhanced turbulent intensity. Theoretical predictions and experimental results both indicated that the recycle ratio increased with the SAH thermal efficiency for all proposed designs. The results show a higher heat transfer efficiency for the proposed four configurations using wavelike corrugated plates compared to those conducted in single-pass and flat-plate absorber plates with up to a maximum 133% (from 0.301 to 0.703) increment. The optimal device performance was examined for all external-recycle configurations under the same working dimensions and operational conditions. The best configuration for optimal thermal performance was the device that lengthened the air flow pathway and increased the air velocity within the collector; thus, a higher heat transfer rate was accomplished. The evaluation of increments in the power consumption and of the heat-transfer efficiency enhancement together determined the optimal design based on an economic consideration across various configurations of cross-corrugated double-pass devices.

Resonance-driven heat transfer enhancement in a natural convection boundary layer perturbed by a moderate impinging jet

We report a convective heat transfer enhancement driven by flow resonance downstream of a natural convection boundary layer that is perturbed by a moderate impinging jet. Our experimental observations and large eddy simulations confirm flow resonance between the thermal boundary layer and a periodic flow at the jet-impinging region. Downstream heat transfer enhancement from the baseline of natural convection exceeds 40%. The results support the development of efficient heat transfer enhancement methods.

Heat transfer and pressure drop characteristics of 3-D finned tube heat exchanger in ash-laden flue gas

As an efficient heat transfer enhancement element, 3-D finned tube has good potential in the field of waste heat utilization of industrial flue gas. However, the industrial flue gas often contains a large amount of ash particles. Meanwhile, ash deposition on the surface of heat exchanger can worsen the heat transfer performance and even shorten the service life of the heat exchanger. Therefore, the research of coupling effect of heat transfer and ash deposition on 3-D finned tube heat exchanger is very necessary, and it is bound to affect the further promotion and application of 3-D finned tube heat exchanger. In this paper, the influence of ash deposition on heat transfer process of 3-D finned tube heat exchanger was further studied. The effects of ash deposition time on heat transfer rate and relative pressure drop were discussed firstly. It was found that both ofheat transfer and relative pressure drop basically tended to be stable with the running time up to 6 hours. Then, the influences of fin height of 3-D finned tube, gas velocity and particle concentration on fouling characteristics, heat transfer and flow performance were studied according to the orthogonal array design method. The optimized parameters corresponding to the smallest fouling coefficient and the least relative pressure drop after fouling were determined. Besides, the performance of 3-D finned tube heat exchanger with the optimized parameters was also compared with other tested heat exchangers. The results showed that the heat exchanger with optimized parameters had better heat transfer performance than the other cases under the same condition. At last, a correlation of fouling coefficient of 3-D finned tube heat exchanger under the optimized parameters with ash deposition time was obtained, and it can be useful in the design and evaluation of heat exchanger in dusty environment.

Experimental Feasibility Study of a Direct Contact Latent Heat Storage Using an Ester as a Bio-Based Storage Material

Latent heat storage (LHS) represents a valuable technology for the integration of intermittent renewable energy sources in existing and future energy systems. Improvements in LHS can be sought by enhancing heat transfer efficiency, compactness and diminishing the environmental impact of storage systems. In this paper, direct contact latent heat storage (DC-LHS) using esters as phase change material (PCM) is proposed as a promising compact storage technology to achieve high performance both in terms of heat transfer and sustainability. The technology allows for the heat transfer fluid (HTF) to flow directly through the PCM, forming a large amount of small droplets and thus providing a large heat exchange surface area between the two materials. At the same time, using biobased esters as PCM, gives the technology clear ecological advantages when compared to alternative types of compact energy storage. Furthermore, no complex heat transfer enhancing structures are necessary in a DC-LHS, further reducing the environmental impact and enabling very high energy densities. In this paper, the feasibility of this concept is explored for the first time by developing and testing an experimental DC-LHS device using methyl palmitate as PCM and water as HTF. The thermal performance and stability of the material combination are analysed by different melting–solidification experiments and distinctive effects are identified and comprehensively discussed for the first time. The basic concept as well as the novel material combination are validated. The study finds the critical challenges that must be overcome in order for this highly promising technology to be successfully implemented.

Conjugated heat transfer of power-law fluids in double-pass concentric circular heat exchangers with sinusoidal wall fluxes.

An analytical formulation, referred to as conjugated Graetz problems, is developed to predict the temperature distribution and Nusselt numbers for the power-law fluid flowing in a double-pass concentric circular heat exchanger under sinusoidal wall fluxes. A new design of inserting an impermeable sheet into a concentric tube, in parallel, to conduct recycling double-pass operations has been studied theoretically in the fully developed region, resulting in substantial improvements in the performance of heat exchanger device. The analytical solution was derived using the complex functions by transforming the boundary value problem into ordinary differential equations with the aid of the Frobenius method. The influences of power-law index and impermeable-sheet position on average Nusselt numbers with various designs and operating parameters are also delineated. The theoretical predictions show that the heat transfer efficiency is considerably improved through operating the double-pass device compared to via a single-pass circular heat exchanger (where an impermeable sheet is not inserted). The economic feasibility of operating double-pass concentric circular heat exchanger for power-law fluids is exemplified by the ratio of the heat-transfer efficiency enhancement and the increment in power consumption. The double-pass effect from increasing the convective heat-transfer coefficient can compensate for the rise in power consumption, which serves as important economic advantage of this design.

A Thermal-Hydraulic-Mechanical Coupling Study of Heat Extraction from the Geothermal Reservoir with a Discrete Fracture Network

The complex thermal-hydraulic-mechanical (THM) coupling is the key issue to the energy extraction from a geothermal reservoir, where fractures are the main channels for fluid circulation and heat transfer. However, the effects of matrix deformation-induced aperture variation and fracture roughness on heat recovery efficiency are unclear. In this paper, a fully coupling THM model based on a discrete fracture network is proposed to explore these coupling effects. First, the fracture roughness and the fracture aperture variation with effective stress are introduced. Second, the water flow and heat transfer in the matrix and fractures as well as the deformation of the geothermal reservoir are individually formulated for a fractured geothermal reservoir. Third, the model is validated with analytical solution for its thermal-hydraulic (TH) coupling effect and literature data for its hydraulic-mechanical (HM) coupling effect. Finally, the features of heat transfer and fluid flow in the fractured geothermal reservoir are comparatively analyzed through four scenarios. The simulation results indicate that the discrete fracture network severely impacts the pressure distribution and temperature advance. The aperture variation induced by solid deformation can enhance heat transfer efficiency, and the fracture roughness can reduce the heat transfer efficiency.

A novel method of enhancing convective heat transfer by dynamic controlling rib

New and efficient mixing heat technology is increasingly demanded for many industrial fields. This paper proposed a novel technique of enhancing convective heat transfer by dynamic controlling rib and investigated several cases of vibration rib controlling flow. The study results of heat transfer coefficient, temperature and turbulent intensity indicate that dynamic flow control is an efficient heat transfer enhancement technique. The dynamic flow control breaks through the current enhancement heat transfer technologies such as general stationary rib and other vortex generators, and achieves a better heat transfer effect. Comparing traditional rib technologies, vibration rib does not only increase heat transfer performance but leads a lower flow resistance. More importantly, it can be dynamically adjusted to achieve better flow turbulence. As a conclusion, the enhancement heat transfer performance can be timely dynamically adjusted to meet the different heat transfer demand by changing timely the frequency and amplitude of vibration rib, which achieves the optimization of whole system thermal protection. New enhancing heat transfer technique effectively improve the comprehensive heat transfer performance, and provides a reference for intelligent thermal control protection system

Investigation of thermophysical properties of aqueous magnesium ferrite nanofluids

Highly stable aqueous nanofluids of magnesium ferrite (MgFe2O4) have been synthesized in various concentrations through a two-step method. Their thermophysical properties are analyzed by studying viscosity and thermal conductivity with respect to the concentration and temperature. The structural analysis of MgFe2O4 nanoparticles reveals their cubic spinel structure, whereas transmission electron microscopy (TEM) analysis confirms the spherical morphology. The magnetic studies of MgFe2O4 nanoparticles show the superparamagnetic behavior. The MgFe2O4 nanofluid exhibits non-Newtonian shear thinning behavior. The viscosity values are fitted with Einstein, Wang, and Chen models. The effective thermal conductivity data of MgFe2O4 nanofluids is compared with Hamilton-Crosser model. The enhancements in viscosity and thermal conductivity with respect to concentration and temperature are investigated. A quantitative comparison of enhancement coefficients of viscosity and thermal conductivity is made to understand the heat transfer performance of MgFe2O4 nanofluids. From the enhancement ratio, it is proved that the prepared MgFe2O4 nanofluids have enhanced heat transfer efficiency.

Parametric analysis on the thermal behavior of cracking hydrocarbon fuel flow inside asymmetry heated cooling channels with micro-ribs

Micro-rib is an efficient heat transfer enhancement method for supercritical fuel in the regenerative cooling channel of advanced aero-engines. The endothermic hydrocarbon fuel would crack into smaller molecules at high temperatures and significantly change fluid properties, giving more complexity for flow and heat transfer in the micro-ribbed cooling channel. In this paper, a three-dimensional simulation model, embedded with a skeletal 22-step cracking mechanism, was established to conduct parametric analysis on thermal behaviors of cracking n-Decane at supercritical pressures in asymmetry heated channels with micro-ribs. The results reveal that thermal cracking would thicken the velocity boundary layer in the channel. Under this circumstance, regular size micro-ribs (h/H ≈ 10%) might abnormally weaken heat transfer of cracking hydrocarbon fuel and higher micro-ribs are required for effective heat transfer enhancement in the channel. Due to the low-density zone caused by cracking products near the heated wall, heat transfer enhancement brought by micro-ribs becomes less sensitive to the increase of micro-rib height. Besides, thermal cracking shortens the range of recirculation zones behind micro-ribs, thus much smaller micro-rib pitch is required for effective heat transfer enhancement. Furthermore, micro-ribs have better heat transfer enhancement performance in higher fuel conversion region, where the density gradient is smaller.

Heat Transfer Efficiency Enhancement of Lithium-Ion Battery Packs by Using Novel Design of Herringbone Fins

Abstract Battery thermal management system (BTMS) is a hot research area for electric vehicles (EVs). Common BTMS schemes include air cooling, liquid cooling, and phase-change materials (PCMs). Air cooling BTMS is widely used in EVs because of its simplicity, high efficiency, and low cost. However, past air cooling BTMS research focused on inlet flow, air channel design, and battery layout. Few studies have focused on improving the heat transfer efficiency of battery packs. This paper aimed to improve the heat transfer efficiency of air cooling BTMS by using herringbone fins. Both inline and staggered arrangements of lithium-ion cells were considered. Moreover, the effects of transverse pitch, longitudinal pitch, fin height, fin number, and inlet velocity were examined. Installation of herringbone fins with optimal values of parameters caused a decrease in average temperature of cells by 3.687 K in the inline arrangement and 4.15 K in the staggered arrangement. Furthermore, a significant improvement in temperature uniformity was also observed. The simulation results will be helpful for the design of air cooling BTMS.

Electro-active Variable-Stiffness Corrugated Structure Based on Shape-Memory Polymer Composite.

Shape-memory polymers (SMPs) can adjust their stiffness, lock a temporary shape, and recover the permanent shape upon an appropriate stimulus. They are applied in the field of morphing skins. This work presents a variable-stiffness corrugated sheet based on a carbon fiber felt (CFF)-reinforced epoxy-based SMP composite that shows variable stiffness and extreme mechanical anisotropy for potential morphing skin applications. The corrugated sheet exhibits a variable stiffness with a change in temperature, which can help the skin adjust its stiffness according to different service environments. The corrugated sheet can be electrically heated rapidly and homogeneously due to its high electrical conductivity and enhanced heat transfer efficiency. Its Joule-heating effect acts as an effective active stimulation of the variable stiffness and shape-memory effect. The CFF-reinforced epoxy-based SMP composite was manufactured into a corrugated shape to obtain extreme mechanical anisotropy. The corrugated sheet shows a low in-plane stiffness to minimize the actuation energy, while it also possesses high out-of-plane stiffness to transfer the aerodynamic pressure load. Its mechanical properties, electrical heating performance, and shape-memory effect were investigated using experiments. The results show that the proposed SMP composite exhibits extreme mechanical anisotropy, considerable deformation ability, and variable stiffness induced by Joule heating without an external heater.

Detached eddy simulation of the flow field and heat transfer in cryogenic nitrogen jet

Cryogenic nitrogen jetting is a promising drilling rate improvement method, in which heat transfer plays an important role in inducing thermal stresses and facilitating rock breakage. In the present study, we aim to study flow field and heat transfer of a cryogenic nitrogen jet in two potential phase states (i.e. liquid and supercritical) under downhole conditions and determine the effect of some critical engineering parameters, including inlet pressure, ambient pressure and standoff distance, which are of concern for field applications of this method. Three different detached eddy simulation (DES) approaches were compared and validated to assess their performances in jet flow issues. These comparisons indicate IDDES showed better performance in predicting the flow field and heat transfer of jet flow, and thus was adopted for the present simulations. According to the simulation results, vorticity, dominant frequency fd of vortex instability and pressure oscillations grow with increasing inlet pressure for both free and impinging jets. Compared to the liquid nitrogen (LN2) jet, the supercritical nitrogen (SCN2) jet has higher vorticity magnitude and fd of temperature fluctuations, causing its vortex rings to breakdown in advance. The dominant frequency of temperature oscillations at the stagnation point falls at the same level as that of vortex instability in the shear layer, revealing the prevailing role of large-scale vortices in heat transfer. Under the same jet pressure condition, the heat transfer rate for SCN2 jet is constantly higher than that of LN2 jet. Increasing inlet pressure helps increase fd of temperature fluctuations and heat transfer rate for both LN2 and SCN2 jets. Under the same pressure difference (between inlet and outlet), lower ambient pressure is more conducive for SCN2 jets to enhance the vortex scale and heat transfer rate. In contrast, the ambient pressure has no significant influence on the LN2 jet. In the range of h/d ≤ 6, higher standoff distance delays the transition of vortex structures in the wall jet zone and contributes to the enhancement of heat transfer efficiency.

Development and application of a solid-state fan for enhanced heat dissipation

The miniaturization and high integration of electronic devices require efficient heat transfer enhancement. The solid-state fan (SSF) based on corona discharge is a good candidate. The SSF shows advantages in energy consumption, size, cost, and operability et al. compared to traditional cooling systems. In this paper, a high performance SSF was proposed and developed for heat transfer enhancement. The generation of corona wind in SSF was explored theoretically, and a velocity correction method was proposed. The operating durability was improved under the action of carbon nanotube and manganese dioxide. The structure and electrical parameters of SSF can be optimized to obtain higher corona wind velocity. A 3.96 m/s corona wind velocity was obtained for the optimized SSF. The prototype of SSF shows better cooling performance for both uniform heat flux and hot spot heat flux. A temperature drop of 22.3 °C can be obtained for a light-emitting diode (LED) at the applied voltage of 6 kV, and the luminous flux decreased by only 1.5%, which is a satisfactory result. A coated SSF can increase the corona wind velocity at the same voltage and minimize the ozone generation to prolong the service life.

Characteristics of heat flow as well as process of heat conduction and transport in partitioned thermal convection

How to improve the heat transfer efficiency of the system is always a hot issue in thermal convection research field. It is found that when the partitions are added at equal distances to the classical physical model -- Rayleigh-Bénard convection system and gaps are left between the horizontal plates and partitions, the heat transfer efficiency of the system increases significantly with the number of partitions increasing. The heat transfer efficiency can reach up to 3.1 times that of the non-partition device with the specific geometric parameters. In this paper, the Direct Numerical Simulation (DNS) method is used to simulate the partitioned convection system. The mechanism of the heat transfer enhancement of the system is analyzed by studying the characteristics of the heat flow as well as the heat conduction and transport in the system. After the flow in partitioned convection system is fully developed, the fluid in each channel moves vertically in alternating direction and the upward(downward) channel has a higher(lower) temperature than the average temperature of the cell. Due to the symmetry of the system, only the bottom region of the low temperature channel, the bottom region of the high temperature channel and the gap region connecting these two channels are selected for research. By discussing the lateral and longitudinal transport processes of heat flow in the above three regions, the heat flux in the channels and gap areas of the system are studied by quantitative analysis. The results show that the low-temperature fluid in the channel impacts on the bottom plate and then moves into the gap area; the fluid is continuously heated by the bottom plate and flows out of gap area with high temperature. Finally, the fluid converges in the heat transfer channel and forms a longitudinal jet. The external input heat flux of the area that has only horizontal heat transport is large, accounting for 92% of the total heat flux which is obtained from the bottom plate. The heat flux of gap area accounts for 64% of the total heat flux, but the external input heat flux of the area that has only longitudinal heat transport is smaller. The convection system with different geometric parameters has the effect of enhancing heat transfer efficiency, and enhancement capability of the system is stronger when the height of gaps is smaller. When the number of partitions &lt;i&gt;n&lt;/i&gt; = 11 and the height of gap &lt;i&gt;d&lt;/i&gt; = 0.01, the value of the global &lt;i&gt;Nu&lt;/i&gt; number is largest, &lt;i&gt;Nu&lt;/i&gt; = 82, which is more than three times that of the system without partitions.