Heat Transfer Process Research Articles

Numerical investigation of CH4/H2/air micro-mixing combustion flow in a micro gas turbine combustor with different head-end structures

In order to investigate the premixed combustion characteristics of CH4/H2/air in a micro-mixing combustor, the effects of different micro-mixing head-ends (HE1, HE2, HE3) and hydrogen mixing ratios on the temperature distribution, heat transfer process, emission characteristic, flames shape are analyzed. The results show that compared with swirl head-end combustion, the micro-mixing combustion performance is better. Among the three head-ends, HE3 has the best combustion characteristics and stable flames. The temperature distribution in the high-temperature zone is uniform, and low-temperature zone is concentrated near the jet, which can suppress the flashback. The velocity and temperature gradient near the central axis of jet streams show a strong synergistic effect. The flames are plume shaped and flames stability is mainly influenced by the H2 combustion process. Increasing the jet diameter, decreasing the jet spacing and increasing the hydrogen mixing ratio all contribute to the flames stability, but these three methods can stabilize the flames by affecting fluid Reynolds number, interaction between small flames and combustion rate, respectively. Moreover, small jet diameter and high hydrogen mixing ratio can reduce OTDF, which contributes to improve outlet temperature uniformity.

3-D stochastic modeling approach in thermal inactivation: estimation of thermal survival kinetics of Escherichia coli O157:H7 in a hamburger after exposure to desiccation stress.

Desiccation tolerance of pathogenic bacteria is one strategy for survival in harsh environments, which has been studied extensively. However, the subsequent survival behavior of desiccation-stressed bacterial pathogens has not been clarified in detail. Herein, we demonstrated that the effect of desiccation stress on the thermotolerance of Escherichia coli O157:H7 in ground beef was limited, and its thermotolerance did not increase. E. coli O157:H7 was inoculated into a ground beef hamburger after exposure to desiccation stress. We combined a bacterial inactivation model with a heat transfer model to predict the survival kinetics of desiccation-stressed E. coli O157:H7 in a hamburger. The survival models were developed using the Weibull model for two-dimensional pouched thin beef patties (ca. 1 mm), ignoring the temperature gradient in the sample, and a three-dimensional thick beef patty (ca. 10 mm), considering the temperature gradient in the sample. The two-dimensional (2-D) and three-dimensional (3-D) models were subjected to stochastic variations of the estimated Weibull parameters obtained from 1,000 replicated bootstrapping based on isothermal experimental observations as uncertainties. Furthermore, the 3-D model incorporated temperature gradients in the sample calculated using the finite element method. The accuracies of both models were validated via experimental observations under non-isothermal conditions using 100 predictive simulations. The root mean squared errors in the log survival ratio of the 2-D and 3-D models for 100 simulations were 0.25-0.53 and 0.32-2.08, respectively, regardless of the desiccation stress duration (24 or 72 h). The developed approach will be useful for setting appropriate process control measures and quantitatively assessing food safety levels.IMPORTANCEAcquisition of desiccation stress tolerance in bacterial pathogens might increase thermotolerance as well and increase the risk of foodborne illnesses. If a desiccation-stressed pathogen enters a kneaded food product via cross-contamination from a food-contact surface and/or utensils, proper estimation of the internal temperature changes in the kneaded food during thermal processing is indispensable for predicting the survival kinetics of desiccation-stressed bacterial cells. Various survival kinetics prediction models that consider the uncertainty or variability of pathogenic bacteria during thermal processing have been developed. Furthermore, heat transfer processes in solid food can be estimated using finite element method software. The present study demonstrated that combining a heat transfer model with a bacterial inactivation model can predict the survival kinetics of desiccation-stressed bacteria in a ground meat sample, corresponding to the temperature gradient in a solid sample during thermal processing. Combining both modeling procedures would enable the estimation of appropriate bacterial survival kinetics in solid food.

Numerical Investigation of the Coaxial Geothermal Heat Exchanger Performance

Space heating and cooling using geothermal heat exchangers is a promising environmentally friendly green energy solution. Modeling these energy storage systems is crucial for optimizing their design and operation. In this context, the present study consists of numerically investigating the effects of various physical properties, including thermal conductivity, density, and specific heat capacity of each material, as well as flow velocity, on the process of heat transfer in vertical geothermal heat exchangers using coaxial pipes to optimize their energy performance. Numerical simulations were carried out using Gambit-Fluent software. Different materials that make up the coaxial heat exchanger structure studied were tested to highlight their effects on the progress of heat flux and temperature. Thermal and fluid mechanics aspects were also studied. At the end of this study, a comparative analysis was carried out using the U-tube geothermal heat exchanger. The results indicate that the heat exchanger using a coaxial tube demonstrates superior thermal efficiency compared to the U-tube configuration. It has been found that using a low velocity with an appropriate selection of tube, grout, and soil materials results in enhanced dynamic exchanges, thereby enhancing the thermal efficiency of the geothermal exchanger.

Consequences of higher order chemical reaction on bioconvective carbon nanotubes flow implementing Buongiorno's model

In recent years, carbon nanotubes have been extensively explored based on numerous applications in fields such as carbon nanotube based electrodes, super capacitors, nanowires, sensors, coating with polymers, biomedical, and mechanical applications. Keeping in view the significance of carbon nanotubes in the heat transfer process in micro-electrochemical systems, this study is conducted to examine the heat transfer attributes of the carbon nanotubes using the mixture base working fluid. The focus of this investigation is to elaborate the consequence of higher chemical reactions on the bioconvective flow of carbon nanotubes. Additionally, modified Buongiorno's nanofluid model has been used, which undertakes thermophoresis and Brownian motion effects. Heated boundary condition has also been incorporated with the migration of motile microorganisms. The hybrid nanofluid mechanism has been followed in this work. Carbon nanotubes of single-layer and multi-layer have been used simultaneously with different working fluids, such as ethylene glycol (EG) and ethylene glycol/water (EG-water). Non-dimensional flow model equations have been tackled with the bvp-4c package. The obtained outcomes have been presented for distinct profiles and tabulated data sets for the surface skin friction and heat transfer coefficient. It has been observed that when the level of Brownian motion increases, the velocity profile decreases abruptly for SWCNT-MWCNT/EG as compared to SWCNT-MWCNT/EG-water hybrid nanofluid. Opposite behavior has been seen with raising values of magnetization. High Prandtl number decrease thermal boundary layer thickness for both types of hybrid nanofluids. The motile microorganism profile expands by raising the level of bioconvective Lewis number. Moreover, the outcomes of drag force and Nusselt number have been compared, and good agreement has been found.

Thermodynamic modeling and performance analysis of photovoltaic-thermal collectors integrated with phase change materials: Comprehensive energy and exergy analysis

Phase change materials (PCMs) integrated with photovoltaic-thermal (PVT) collectors can simultaneously generate and store electrical and thermal energy. However, design optimization requires accurate modeling of the complex heat transfer processes in PCMs under varying operating conditions. This study introduces an efficient simulation approach with generalized Nusselt number correlations to enable precise and rapid analysis of PCM thermal performance. A numerical model is developed to quantify heat fluxes, node temperatures, energy and exergy outputs across PCM solid, melting, and liquid states. Extensive analysis is conducted to explore the impact of irradiation, ambient temperature, PCM thickness, tilt angle, and wind speed on PVT performance. Key findings include: (1) thermal energy yield exceeds electrical output by 2.8 times owing to PV's low efficiency, while electrical exergy dominates thermal exergy by 5.3 times highlighting electric output's primacy; (2) electrical output chiefly depends on irradiation, while thermal energy and exergy are highly sensitive to ambient temperature and wind speed; (3) thermal energy escalates 4.5 times faster than electrical energy with irradiation rise, but thermal exergy drops sharply from 10.1 to 0.34 W as ambient temperature increases from 0 to 35 °C due to quality factor degradation. The study provides new generalized correlations, validated model, and extensive performance assessment to advance PCM-based PVT collector design.

Sodium alginate-based MHD ternary nanofluid flow across a cone and wedge with exothermic/endothermic chemical reactions: A numerical study

The use of magnetohydrodynamic ternary nanofluid flow for heat transfer is essential in various industrial and commercial applications. This work examines heat transfer over cone and wedge shapes with Sodium Alginate-based ternary nanofluid flow, considering the effects of activation energy and exothermic/endothermic processes. Using similarity transformations, the controlling set of partial differential equations is converted into a network of interconnected nonlinear ordinary differential equations. Numerical solutions using the Runge-Kutta Fehlberg 4th 5th order method and shooting approach offer insights into the effects of several dimensionless factors. The outcomes show that the magnetic field parameter is crucial in lowering fluid velocity within a cone more efficiently than a wedge. Due to activation energy considerations, the cone shape notably impacts heat transmission in exothermic reactions, but the wedge geometry is more effective in endothermic reactions. Concentration profiles rise with activation energy and fall with increasing chemical reaction rates. The rate of thermal distribution is 48.68% more in wedge than cone geometry for the exothermic case and 35.57% in the endothermic case while the rate of mass transfer is higher in cone geometry than wedge geometry, about 7.83% in the exothermic case and 19.27% in the endothermic case. The present study has many applications, including optimizing heat transfer processes in sectors such as thermal systems, energy generation, and electronics. Additionally, it may be used to guide the design of magnetically affected systems and provide assistance for uses in chemical engineering.

Multiscale study of reactive transport and multiphase heat transfer processes in catalyst layers of proton exchange membrane fuel cells

Improving the performance of proton exchange membrane fuel cells (PEMFCs) requires deep understanding of the reactive transport processes inside the catalyst layers (CLs). In this study, a particle-overlapping model is developed for accurately describing the hierarchical structures and oxygen reactive transport processes in CLs. The analytical solutions derived from this model indicate that carbon particle overlap increases ionomer thickness, reduces specific surface areas of ionomer and carbon, and further intensifies the local oxygen transport resistance (Rother). The relationship between Rother and roughness factor predicted by the model in the range of 800-1600 s m-1 agrees well with the experiments. Then, a multiscale model is developed by coupling the particle-overlapping model with cell-scale models, which is validated by comparing with the polarization curves and local current density distribution obtained in experiments. The relative error of local current density distribution is below 15% in the ohmic polarization region. Finally, the multiscale model is employed to explore effects of CL structural parameters including Pt loading, I/C, ionomer coverage and carbon particle radius on the cell performance as well as the phase-change-induced (PCI) flow and capillary-driven (CD) flow in CL. The result demonstrates that the CL structural parameters have significant effects on the cell performance as well as the PCI and CD flows. Optimizing the CL structure can increase the current density and further enhance the heat-pipe effect within the CL, leading to overall higher PCI and CD rates. The maximum increase of PCI and CD rates can exceed 145%. Besides, the enhanced heat-pipe effect causes the reverse flow regions of PCI and CD near the CL/PEM interface, which can occupy about 30% of the CL. The multiscale model significantly contributes to a deep understanding of reactive transport and multiphase heat transfer processes inside PEMFCs.

A Modified Enthalpic Lattice Boltzmann Method for Simulating Conjugate Heat Transfer Problems in Non-Homogeneous Media

A Modified Enthalpic Lattice Boltzmann Method for Simulating Conjugate Heat Transfer Problems in Non-Homogeneous Media

Review of Modeling Approaches for Conjugate Heat Transfer Processes in Oil-Immersed Transformers

This review addresses the modeling approaches for heat transfer processes in oil-immersed transformer. Electromagnetic, thermal, and hydrodynamic thermal fields are identified as the most critical aspects in describing the state of the transformer. The paper compares the implementation complexity, calculation time, and details of the results for different approaches to creating a mathematical model, such as circuit-based models and finite element and finite volume methods. Examples of successful model implementation are provided, along with the features of oil-immersed transformer modeling. In addition, the review considers the strengths and limitations of the considered models in relation to creating a digital twin of a transformer. The review concludes that it is not feasible to create a universal model that accounts for all the features of physical processes in an oil-immersed transformer, operates in real time for a digital twin, and provides the required accuracy at the same time. The conducted research shows that joint modeling of electromagnetic and thermal processes, reducing the dimensionality of models, provides the most comprehensive solution to the problem.

Turbulent Rayleigh–Bénard convection in a supercritical [formula omitted]-based binary mixture with cross-diffusion effects

CO2-based binary mixtures are promising in energy engineering to improve efficiencies of thermodynamic cycles where supercritical CO2 prevails. Indeed, under supercritical pressure and transcritical temperature conditions, special thermophysical properties of binary mixtures make the heat transfer process accompanied by enhanced cross-diffusion effects, i.e., the Soret effect and the Dufour effect. Their influences on heat transfer have not been well understood yet. This paper numerically investigates turbulent Rayleigh–Bénard convection in CO2-C2H6 binary mixture. Calculations are performed based on a spectral element method solver considering various temperature differences and pressures. Results indicate that the flow field presents a double-vortex structure. The thickness of the boundary layer is negatively correlated with the flow intensity. Under a positive separation ratio, the concentration gradient induced by cross-diffusion effects enhances buoyancy, which in turn reinforces the natural convection and heat transfer. The enhancement becomes stronger as the critical pressure is approached. Turbulent fluctuations are also strengthened by cross-diffusion effects, except for temperature fluctuations. The unusual reduction in temperature fluctuations is attributed to the increased size of the thermal plume caused by the Dufour effect.

The mechanism by which thermal coupling leads to an asymptotic maldistribution stability boundary for flow boiling in parallel channels

Phase change heat transfer processes are attractive for the efficient thermal management of advanced semiconductor devices, with flow boiling in parallel microchannel heat sinks being one promising solution. However, there are several implementation challenges associated with two-phase flow in parallel microchannels, particularly flow maldistribution, which can adversely affect performance and reliability. Two-phase flow models can be useful in predicting and understanding the instability mechanisms that leads to maldistribution, such that parametric performance trends and safe regions of operation can be identified. Channel-to-channel thermal coupling has been shown to alleviate maldistribution, but it is not yet understood why this effect is limited to some critical lateral thermal conductance above which there is no further benefit. In the current work, a two-phase flow model with a lumped thermal capacitance representation of the heat sink wall is developed to identify the mechanism for this asymptotic maldistribution stability boundary for thermally coupled microchannels. The lumped model allows the nature of stability boundary to be explained via a scaling analysis of the eigenvalues. In such systems, it is identified that a single eigenvalue determines the occurrence of flow maldistribution. Scaling analysis shows that, for small values of thermal conductance, this eigenvalue becomes a quadratic function of thermal coupling, which enhances the stability of microchannels and moves the stability boundary. However, for large values of thermal conductance, the eigenvalue is dependent only on the fluid properties, leading to a limit at which thermal coupling can no further improve stability or affect the stability boundary. The lumped model developed in this work enables mechanistic understanding of the role of channel-to-channel thermal coupling on mitigating flow maldistribution and therefore may offer important guidance on the design of flow boiling systems and heat sinks.

Study on the flame radiative heat transfer and near-field radiation heat flux predictive model of vehicle fires in a tunnel

As a major form of heat transfer, flame thermal radiation has an important effect on the ignition of adjacent energy, fire spread and environmental damage. Forecasting the flame radiation heat flux can provide theoretical basis for fire hazard assessment, fire extinguishing and salvation. Meanwhile, the distinctive structure of the arc tunnel can result in significant variations in the local heat and mass transfer processes during tunnel fires compared to those in rectangular tunnels, leading to different fire characteristics parameters. In this study, experiments and theoretical analyses were conducted to investigate the flame length scale and near-field radiation heat flux on the lower surface of an arc-shaped ceiling induced by vehicle fires in a tunnel. The findings reveal that the flame length scale in the transverse direction beneath the arc-shaped ceiling decreases with an increasing burner aspect ratio and increases with the increasing heat release rate. A dimensionless model of the flame length scale under the arced ceiling with various burner aspect ratios was proposed based on the amount of remaining unburned fuel after flame impingement and the buoyancy component along the arc-shaped ceiling. Simultaneously, radiative heat fluxes on the lower surface also increase with rising heat release rate. The flame geometry beneath the arc-shaped ceiling is assumed to be a combination of a cuboid and an arc plate model based on the actual flame length scale. Subsequently, the view factor, radiative fraction, and flame surface area are analyzed to predict the radiative heat fluxes on the lower surface. The predictions of the cuboid and arc plate flame model show good agreement with the current experimental data. This work presents a dimensionless correlation of the flame length scale and calculates the view factor between the target and the arc plate to predict the near-field radiative heat flux more accurately. This approach also facilitates the understanding of flame spreading behavior and thermal hazards impacted by arced ceiling.

Waste heat recovery of blast furnace slag in moving bed: Influencing of structural parameters and operating parameters

Physical recovery of waste heat from blast furnace slag (BFS) by a moving bed is a promising solution. The heat recovery of BFS is mainly achieved through gas–solid heat exchange with cold air and solid–solid heat exchange with water in a moving bed. In this study, the heat transfer process of BFS particles with a particle size ranging from 0.5 mm to 3.0 mm in a rectangular, trapezoidal variable cross-section moving bed was analyzed numerically. The influence of structural parameters and operating parameters of variable cross-section moving beds on heat recovery of BFS was studied. The research found when the inclination angle of the moving bed was 50°, the cooling airspeed was 0.3 m·s−1, and the discharge rate was 0.9 g·s−1, it can not only satisfy the cooling of particles below 400 K, but also ensure that the cooling efficiency of the particles in the bed was higher than 92 %. In this working condition, the improvement of cooling effect and the suppression of reheating could be realized at the same time. Meanwhile, the impact caused by excessive airspeed was weakened, and so was wall wear and dust removal device complexity. The study also found that laying a water-cooled wall can reduce the area of the dead zone of heat exchange and the particle temperature in the dead zone and ensure that the discharge temperature was lower than 380 K.

Heat transfer error analysis of high-temperature wall temperature measurement using thermocouple

Thermocouples are widely employed as the temperature measuring element for an aero-engine. However, due to the unique characteristics of the aero-engine test environment, there exist significant temperature measurement errors of the thermocouple. The steady-state heat transfer error of the thermocouple can be attributed to convection heat transfer error, wire heat transfer error, and radiation heat transfer error. The flow and heat transfer process of wall temperature measurements using armored K-type thermocouples were simulated numerically by Fluent software at the Mach number of 0.1–0.5 and the temperature of 700∼1200 K. The results indicate that convective error accounts for more than 55 % of the total transfer error. To reduce excessive temperature measurement errors, a novel airflow stagnation cover structure around the thermocouple was presented. When the diameter of the stagnation cover is 2 mm, the error of the thermocouple is reduced to less than 1 %.

Performance optimization of non-isothermal endoreversible chemical pump via Lewis analogy

By considering heat and mass transfer (HMT) coupling, an endoreversible non-isothermal chemical pump cycle model is established and the optimal performance is studied herein. Assuming that the HMT follows Lewis analogy (heat transfer (HT) process obeys Newton's HT law and mass transfer (MT) process obeys diffusion MT law), rate of energy-pumping (Σ) and its corresponding vector coefficient of performance (χT and χμ, which are defined herein) are deduced analytically. Based on the general optimization results, the special examples of endoreversible Carnot heat pump with Newton's HT law and the endoreversible isothermal chemical pump with diffusion MT law are further deduced. The effects of heat flux rate (q1) and mass flux rate (g1) on the optimization results are analyzed. The Σ increases with the increases of q1 and g1. The surface of Σ to [χT,χμ] is a monotonically decreasing plane, and the Σ decreases with the increases of χT and χμ. The special cases of endoreversible Carnot heat pump with Newton's HT law and endoreversible isothermal chemical pump with diffusion MT law are further obtained. The Σ and χμ obtained by endoreversible non-isothermal chemical pump are larger than those obtained by endoreversible isothermal chemical pump. Coupling effect of HMT increases Σ and χμ, but correspondingly decreases χT.

New design concept and thermal performance of a composite wall applied in solar greenhouse

Traditional solar greenhouse wall combines the functions of heat preservation and heating. It cannot accommodate both heat storage and insulation that the heat stored in the wall is uncontrollably lost as the temperature difference between the interior and exterior increases. This study proposed a novel composite wall (NCW) with an independent modular wall made of expanded polystyrene board and reinforced concrete (EPCW), and a solar water heating system (SWHS). The thermal properties of traditional brick walls and novel composite walls were assessed through field tests. Numerical simulations were utilized to analyze the heat transfer processes occurring within the wall, enabling determination of the magnitude of heat transfer towards both the interior and exterior. The thermal resistance of the ECPW with the same thickness is 1.5 times higher than that of clay bricks. Meanwhile, the heat loss from the exterior wall is reduced by 44 % through the EPCW. The SWHS installed on the greenhouse north wall increases heat storage by 89 % and heat release by 256 %. The greenhouse annual input cost for using NCW is 2.5 USD m−2 year−1 in 20-year life. It is 32.4 % lower than that of a conventional clay brick greenhouse, and has some promotional and application value.

Features of heat/mass transfer and explosive water boiling at the laser fiber tip

Experimentally, as well as using numerical simulation methods, the features of the processes of heat and mass transfer and explosive boiling of water, initiated by continuous laser radiation with λ = 1.94 μm, emerging from the tip of the laser fiber, are studied. The trajectories of the microvolume with the maximum temperature of the superheated liquid under laser heating, in which the probability of explosive boiling up is maximum, are determined. The calculations took into account changes in the density of superheated water and the dependence of the absorption coefficient of laser radiation on temperature. Using acoustic methods and high-speed video recording, it is shown that during explosive boiling up, the duration of the leading front of the acoustic signal is ∼300 ns. Such a long duration of pressure rise at the receiving point is explained by the fact that explosive boiling occurs in a wide area of superheated liquid near fiber tip, when the nuclei located in it are stimulated by an initially arising pressure pulse.

Membrane role in heat and mass transfer resistance distribution and performance of hollow fiber membrane contactor for SGMD desalination

Hollow fiber membrane contactor (HFMC) is the core device of heat mass exchange between seawater solution and sweeping air in sweeping gas membrane distillation (SGMD) desalination. In order to reveal the distribution of heat and mass transfer resistance on feed solution side, porous membrane side and sweeping air side, a mathematical model considering the simultaneous heat mass transfer and water vapor diffusion mechanism in the membrane pores was established for the cross-flow HFMC. The simulation results of the model were compared with experimental results and literature results. Comparison shows that the deviation of simulation results of the model is less than 13.4 %, which verifies the accuracy and reliability of the simulation results. Influences of the main structural characteristics of porous membrane on the resistance distribution of heat and mass transfer, efficiency and membrane flux were explored. Air side dominates the heat transfer process, while the membrane side accounts for less than 39 % of the total heat transfer resistance for the main range of membrane microstructure parameters investigated. The mass transfer is controlled by the porous membrane except for thin membrane with a thickness of less than 100 μm. Membranes with porosity above 0.8 and as thin as possible can achieve better mass transfer efficiency and freshwater flux. Increasing mean pore diameter has a strong promotion effect on the increase of membrane flux before it reaches 150 nm, and beyond this critical value, the water vapor diffusion mechanism changes from Knudsen collision to molecular collision. Effects of different operating parameters and membrane microstructure parameters on air temperature distribution and humidity distribution were also analyzed.

Numerical Study of Fluid Flow in a Gyroid-Shaped Heat Transfer Element

This paper deals with the design of porous geometry of a heat transfer element. The proposed geometry combines a gyroid triply periodic minimal surface with the recursive principle of geometric body creation. The designed geometry is based on an attempt to increase the heat transfer surface while eliminating negative impacts on the fluid characteristics in the form of pressure loss or increase of the friction coefficient. The proposed geometry of the heat transfer element was compared with a pair of geometries based on the basic gyroid shape but with different channel size parameters. A numerical simulation was performed in Ansys Fluent 2020 R1 using the SST k-omega turbulence model for flow velocities in the range of 0.01 m.s−1 to 0.5 m.s−1, which covered a wide range of the Reynolds number and thus also flow forms in terms of the turbulence intensity. The presented results clearly show lower values of pressure loss and friction coefficient of the proposed geometry compared to the evaluated porous structures. Also, at the same time, they describe the factors positively influencing the mixing process of the liquid in the proposed element, which leads to an increase in the efficiency of the heat transfer process.

Design of CuS composite carbon-based Ni Al-LDH multifunctional phase change composite with electromagnetic shielding performance and heat storage capacity

CuS-based composites are widely used in the fields related to photothermal energy storage and electromagnetic shielding and are excellent candidates for composites with phase change materials. To meet the requirements of micro-integration and electromagnetic resistance of electronic products and optimize the thermal management of electronic products, it is necessary to prepare new flexible composite phase change materials. In this paper, through the design of MPC@Ni Al-LDH/CuS double-layer structure, two-step vacuum filtration method is used, and the highly conductive materials CuS and MPC are introduced into the manufacture of PCM films. With the help of Ni Al-LDH, flame retardancy is introduced. The electromagnetic wave absorption performance is enhanced, and the existence of nano-cellulose (CNF) makes the film have excellent mechanical properties. Ni Al-LDH/MPC and CuS substrates with stable and high mechanical properties are prepared by ultrasonic treatment. According to scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and thermogravimetry (TG) characterizations, PEG successfully entered the MPC/CuS skeleton by vacuum filtration, and flexible phase change composite bilayers (MLPC) were obtained. Due to the synergistic effect of structure and components, the obtained composite film has many different excellent functions. Specifically, when MPC@Ni Al-LDH is 15 wt%, the phase transition enthalpy, thermal conductivity, electromagnetic shielding, and electrical conductivity are 146.8 J/g, 1.07 W/m·K, 38.8 dB and 126.4 S/m, respectively. The 3600 s infrared temperature measurement results show that the sample has stable thermal properties. Due to the presence of CuS, when MPC@Ni Al-LDH is 5 wt%, its absorbance can be kept at 1.51 L/(g·cm), and its photothermal conversion efficiency can reach 90.6 %. The MPC/CuS structure in the composite film provides many heat transfer channels, which reduces the phonon scattering in the heat transfer process and significantly increases thermal conductivity. Therefore, this multifunctional flexible phase change film can be used in photothermal conversion devices and for thermal management of electronic equipment, and it has broad application prospects in wearable equipment design due to its excellent electromagnetic shielding ability and infrared thermal stealth ability.