Discrete Ordinate Model Research Articles

Exergy Efficiency and Energy Efficiency of Double Air Pass Solar Tunnel Air Dryer: A CFD Analysis

This work presents, the computational fluid dynamics simulation of a forced convection double air pass solar tunnel drying system to study the temperature distribution, the flow behaviour of the air stream, and the exergy performance. Realizable k-epsilon non-equilibrium wall function turbulence model, discrete ordinate radiation model, and species transport were used. The average temperature, thermal efficiency, and exergy efficiency were found to 59.2 oC, 30%, and 9.41%, respectively. The result revealed that the uniform temperature and velocity distribution throughout the heating and drying chamber. Therefore, the newly developed double air pass solar tunnel dryer enhances the air temperature and the exergy performance leads to the increment of drying rate and reduction of drying period.

A platinum-coated staggered reactor to intensify lean hydrogen/air combustion: A large eddy simulation study

Catalytic-aided combustion has been proven effective for premixed hydrogen/air mixtures, particularly under lean to ultra-lean conditions. However, minimising the required catalyst sets a significant challenge because noble metals with high catalytic activity are rare and expensive. Therefore, this study aims to intensify the catalytic combustion process by investigating a non-planar reactor comprising an array of platinum-coated half- and full-cylinders through large eddy simulation. A premixed mixture with a fuel-lean equivalence ratio of 0.15 and an incoming Reynolds number of 3500 based on hydraulic diameter is used. For comparison, a planar reactor without cylinders is also studied under the same operating conditions and with the same amount of platinum-coated surface area. The simulation employs the turbulent kinetic energy sub-grid model and the eddy dissipation concept to model the turbulent catalytic reacting flow. The discrete ordinate model is used to account for radiation heat transfer in the catalytic process. Numerical simulations are validated against experimental results prior to analysis. The findings indicate that the placement of cylinders along the reactor length enhances convective mass transfer and intensifies catalytic combustion, resulting in effective combustion over a smaller catalytic surface. Compared to planar models, non-planar reactors demonstrate a much better H2 conversion efficiency throughout the reactor length, saving nearly 62.5 % of the catalyst.

Enhancing building energy efficiency: Innovations in glazing systems utilizing solid-solid phase change materials

This study investigates the energy efficiency of a double-glazing window (DGW) integrating a solid–solid phase change material (SSPCM) with limited thickness, applied to the inner glass pane within the air gap. Numerical model, validated against experimental data, is developed using a finite volume method in ANSYS Fluent. In this model, the Discrete Ordinates (DO) model is applied to simulate radiation, while the enthalpy-porosity approach is used to capture the solidification and melting processes in the phase change material. With this model, the energy performance of the system is analyzed under various transient temperature values (10 to 30 °C) and ranges (1 to 5 °C) during the coldest and hottest days of the year, as well as during cloudy and sunny days in Montreal (Dfb), Vancouver (Cfb), and Miami (Aw). According to the obtained results in Montreal, the DGW-SSPCM system consistently saves energy under summer sunny conditions, with optimal performance when the SSPCM remains transparent. However, it incurs energy losses in cloudy days, where the energy lost is 2.3 times greater than the energy saved in sunny days. In Vancouver, the system shows consistent energy savings, particularly at Tc = 30 °C, with average savings of 20.5 kJ (23 %) under summer sunny conditions. The system is most beneficial in Vancouver, where winter energy savings in cloudy days (50.6 kJ) are 7.1 times greater than the losses in sunny days (7.1 kJ). In Miami, the system results in energy losses by 60 % and 5 % (at Tc = 30 °C) under both summer sunny and cloudy conditions, respectively, indicating unsuitability for its climate. During winter sunny conditions, all three cities experience energy losses, with Vancouver showing the lowest of 7.1 kJ (3 %) and Montreal the highest of 64.4 kJ (19 %) at Tc = 30 °C. In winter cloudy conditions, the system saves energy in all cities, with the highest savings in Miami of 54.5 kJ (26 %) at Tc = 30 °C. Overall, the SSPCM-DGW system has proven to be beneficial in Vancouver across various conditions in terms of energy and visual performance. These findings highlight the necessity of considering localized climate factors when designing and implementing energy-efficient glazing systems. Finally, the SSPCM-DGW system has provided complete visual clarity during office hours, making it more suitable for commercial buildings.

A Comparative study on novel active cooling and heat recovery techniques for photovoltaic-thermal collectors

In this study, four different cooling techniques with a variety type of coolant for a commercial photovoltaic-thermal collector have been simulated optically and thermally by using the discrete ordinate radiation model (DO) and compared in a hot climate. These methods include a cooling channel with lateral inlet and outlet (case II), a cooling channel with uniquely designed fins (case III), a channel with circular inlet and many elliptical outlets patterns (case IV), and a specific pattern of copper tubes containing water beneath the solar module (case V), in comparison with a standard PV module (case I). The cooling fluids utilized in this research consist of dry air, moist air with relative humidity of 20 %, 40 %, and 60 %, and water in an active cooling method. The results indicate that using fins and copper pipes reduces the temperature, respectively, by 12 °C and 23 °C, leading to 4.10 % and 7.92 % improvement in electrical efficiency, which corresponds to a power improvement of 4.12 % and 7.98 % in cases III and V. In comparison, in cases II and IV, temperature reductions were only 6.5 °C and 9 °C, respectively, leading to a smaller improvement in efficiency of 2.20 % and 4.10 % in both scenarios where no fins are present. Consequently, the shape of the inlet and outlet, along with the distribution of air inside the channel, influences the cooling performance of the solar module significantly. It is observed that in cases II, III, and IV, by increasing the relative humidity of the incoming air to 60 % with an inlet velocity of 1 m/s, the electrical efficiency improves approximately 4.21 %, 5.5 %, and 4.91 %, respectively, compared to Case I.

Numerical investigation of optical characterization of polycarbonate panels

Polycarbonate panels (PC panels) are state-of-the-art transparent insulating materials widely used in the construction industry due to their cavity structure, which provides exceptional thermal insulation and optimal optical performance. However, the inherent anisotropy of the three-dimensional cavity structure complicates radiative transfer and requires consideration of both azimuth and zenith angles in optical performance evaluation. This aspect has received limited attention in existing research. This study aims to accurately characterize the optical performance of PC panels through numerical simulations. A three-dimensional radiative transfer model based on the discrete ordinate radiation model is developed to solve the radiation transfer equation. The model's independency regarding mesh division, angular discretization, and accuracy is validated. The effects of incidence angle, geometric parameters, and optical properties of PC panels on optical performance are analyzed. The findings reveal a strong correlation between transmittance and absorption with variations in incident zenith and azimuth angles. The transmittance exhibits a consistent monotonic variation expressible as a rational bifunction. Notably, absorption peaks occur within specific solid angle ranges, with increased structural complexity resulting in heightened absorption and greater uncertainty. For conventional PC materials, maximum transmittance ranges from 46.9 % to 73 %, while maximum absorption ranges from 2.3 % to 13.5 %. Increasing absorption coefficients, refractive index, and surface scattering coefficients nonlinearly decrease transmittance while increasing absorption. Additionally, deviations in transmittance and absorption with azimuth angle amplify with an increase in non-horizontal structures. Sensitivity analysis indicates a significant influence of zenith angle on transmittance, and absorption coefficient predominantly affects absorption.

Numerical simulation and optimization of the multi-stage air/gas supply system in a coke oven battery with 7.1 m coking chambers

ABSTRACT 3-D numerical simulations based on diffusion combustion technology were employed to optimize the multi-stage air/gas supply system in a coke oven battery with 7.1 m coking chambers. In the heating flues, the Eddy-Dissipation Concept (EDC) model and the ideal gas model were utilized to numerically investigate diffusion combustion. What is more, the radiation between the flue gas and the silicon brick was calculated using the Discrete Ordinates (DO) model. After validating the reliability of the model with field-measured data, insights into the temperature field and gas flow in the heating flue, and heat flux distribution over the heating wall were obtained. To characterize the vertical heating uniformity, an index of the standard deviation of the heat flux over the vertical heating walls was proposed. By optimizing the multi-stage air/gas supply design of heating flues, the vertical heating uniformity was improved by 60% according to the index values. The approach developed in this work can be a useful tool for the design of large-capacity coke oven batteries at different scales.

An improved BRDF hotspot model and its use in VLIDORT for studying the impact of atmospheric scattering on hotspot directional signatures in the atmosphere

Abstract. The term “hotspot” refers to the sharp increase in the reflectance occurring when incident (solar) and reflected (viewing) directions almost coincide in the backscatter direction. The accurate simulation of hotspot directional signatures is important for many remote sensing applications. The RossThick–LiSparse–Reciprocal (RTLSR) bidirectional reflectance distribution function (BRDF) model is widely used in radiative transfer simulations, and the hotspot model mostly used is from Maignan–Bréon, but it typically requires large values of numerical quadrature and Fourier expansion terms in order to represent the hotspot accurately for its use coupled with atmospheric radiative transfer modeling (RTM). In this paper, we have developed a modified version based on the Maignan–Bréon's hotspot BRDF model that converges much faster numerically, making it more practical for use in the RTMs that require Fourier expansion of BRDF to simulate the top-of-atmosphere (TOA) hotspot signatures, such as in the RTM models using the Doubling–Adding or discrete ordinate method. Using the vector linearized discrete ordinate radiative transfer model (VLIDORT), we found that reasonable TOA–hotspot accuracy can be obtained with just 23 Fourier terms for clear atmosphere and 63 Fourier terms for atmosphere with aerosol scattering. In order to study the impact of molecular and aerosol scattering on hotspot signatures, we carried out a number of hotspot signature simulations with VLIDORT. We confirmed that (1) atmospheric molecule scattering and the existence of aerosol tend to smooth out the hotspot signature at the TOA and that (2) the hotspot signature at the TOA in the near-infrared is larger than in the visible, and its impact by surface reflectance is more significant. As the hotspot amplitude at the TOA with aerosol scattering included is smaller than that with molecular scattering only, the amplitude of hotspot signature at the surface is likely underestimated in the previous analysis based on the POLDER measurements, where the atmospheric correction was based on a single-scatter Rayleigh-only calculation. This modified model can calculate the amplitude of the hotspot accurately, and, as it agrees very well with the original RossThick model away from the hotspot region, this model can be simply used in conditions with and without hotspots. However, there are some differences in this modified model compared to the original Maignan–Bréon model for the scattering angles close to the hotspot point; thus, it may not be appropriate for those who need an exact representation of the hotspot angular signature.

Numerical investigation on performance of a solar chimney power plant with different absorber configurations

AbstractA solar tower system is a nonpolluting solar thermal power plant that utilizes a combination of a wind turbine and generator to convert thermal energy generated from a solar collector into electrical energy. The study focuses on a system comprising a solar collector that transforms solar energy into thermal energy, a chimney that converts thermal energy into kinetic energy, and a wind turbine that further converts kinetic energy into electrical energy. The system's performance is evaluated through the implementation of a numerical model, which is validated by comparing it with experimental data. Four different types of meshes are tested to determine the most suitable mesh for the system. The discrete ordinate radiation model is used to solve the radiative transfer equation, and the RNG k‐𝜀 turbulence model is implemented to calculate turbulence. In a subsequent study, the effect of absorber configuration on the system's performance is investigated. Three different absorber configurations—sinusoidal, square, and triangular—are proposed, and the numerical results showed that the system's performance is affected by the absorber configuration. The velocity in the chimney inlet increases for all proposed configurations compared to the standard configuration, with the triangular configuration showing the highest velocity increase. Additionally, the newly proposed configurations enhance the thermal efficiency of the system, leading to a thermal efficiency of 12.18%, 12.2%, and 13.65% for the sinusoidal, triangular, and square configurations, respectively. Overall, the solar tower system demonstrates its potential as a clean and efficient source of electrical power.

Improving solar still productivity via fin optimization: computational and experimental investigations

ABSTRACT Solar desalination offers a promising solution to conserve energy and meet the growing demand for freshwater. To improve the productivity of solar stills, the incorporation of fins on the absorber has been explored. This study aims at investigating the impact of various fin geometric parameters on solar still efficiency using an experimentally validated Computational Fluid Dynamics (CFD) model. The study specifically examines the height, width, and spacing between the fins, with three levels assessed for each parameter. Solar radiation and temperature distributions are measured through an experimental design. The discrete ordinate (DO) model is used to capture the solar radiation, while the k-ε Renormalization-group (RNG) is employed to investigate the effect of the turbulence. To ensure mesh independent results, a grid size independence test is conducted. The CFD results are validated against experiments, demonstrating an error less than 4%. The findings show that fins having a height of 30–50 mm increase basin temperature by 2.6%, boosting freshwater productivity by 0.03 l/m2.h, and improving solar still efficiency by 1.74%. Widening fin width raises water basin temperature by 10.4%, resulting in 4% efficiency enhancement. Reducing fin spacing from 130 mm to 30 mm increases productivity by 0.04 l/m2.h, which corresponds to 2.48% efficiency improvement. These findings suggest a careful consideration of fin design parameters can further enhance this efficiency.

A numerical study of cucurbit cultivation in a greenhouse under direct solar radiation and equipped with a direct evaporative cooler in summer season

The performance of direct evaporative cooler to meet cooling demand of a greenhouse in Tehran in the hottest months of the year as well as water and electricity consumption were numerically studied. The suitable values of air change per hour (ACH) was also obtained for cultivation of tomato, cucumber, eggplant and bell peppers. The k-Ԑ Realizable Turbulence and Discrete Ordinates (DO) models was used for simulating the airflow and estimating radiative heat transfer, respectively. The results showed that an ACH of 10 is proper for tomato cultivation. When the ambient temperature is maximal, an ACH of 15 can be used for cucumber cultivation. However, ACH cannot be kept constant, and ACHs of ≤10 should be utilized when the ambient temperature decreases. For eggplants, it is better to use an ACH 20 at hot hours and an ACH of 10 when the temperature declines. For the bell pepper plant, 20 and 10 ACHs are suitable for day and night hours, respectively. Moreover, the maximum daily water consumed in the greenhouse happens in August and equals 222 lit/day for 20 Air Changes per Hour (ACH). The minimum daily water is consumed in July, equaling 106 lit/day for an ACH of 10. In the present study, the electricity rate consumed in the greenhouse equals 127W when ACH = 20, i.e., the consumed electric energy is 3 kWh for the entire system in a 24-h interval.

CFD modelling of the microclimate of a cultivated greenhouse: A validation study between experimental and numerical results

In this work, we present the validation of a numerical model of a greenhouse thermally in-sulated on three sides with a tomato crop. A CFD software (Ansys-Fluent) was used to solve the numerical model. The discrete ordinate model was included to solve the radiative trans-fer equation. The results of the numerical model were compared with the values of air tem-perature observations at different points in the greenhouse. Good agreement was obtained between the simulated and measured values, with coefficients of determination R2 = 0.77, R2 = 0.84, R2 = 0.99, and R2 = 0.89 for the temperatures of the points 10 cm, 80 cm, and 210 cm above the ground and the average temperature in the greenhouse, respectively. A third-order polynomial curve was drawn between the simulated and measured values of relative humidity in the greenhouse. These R2 values are 0.9786 and 0.7165, the simulated and measured relative humidity, respectively. The simulation results showed low velocity values with an average of 0.525 m/s located between 1.5 m and 2 m from the ground.

Personalized kitchen air supply for reducing individual thermal discomfort and cooking pollution intake

High ambient temperature and cooking activities that produce pollutants and waste heat usually make the indoor air quality and thermal environment of residential kitchen unfavorable in summer. Personalized kitchen air supply (PKAS) could be applied to relieve the thermal discomfort and cooking pollution intake of cooking staff. This paper investigated a personalized air supply method of residential kitchen in summer. The residential kitchen was depicted in computational fluid dynamics simulation by realizable k-ε model and discrete ordinate radiation model to reflect the complex thermal characteristics of stove. Based on orthogonal analysis, exhaust rate, exhaust outlet baffle width, and supply air angle were significant factors affecting the concentration of pollutant in kitchen space, whereas exhaust rate and air supply rate were significant factors affecting the intake fraction. Single-factor analysis was further conducted to find better parameter configurations of PKAS for pollutant control. Then, thermal comfort experiments with and without air supply were carried out. When the air supply volume was 280 m³/h and the air supply temperature was 21 °C, the thermal discomfort of subjects can be effectively improved against an uncomfortable condition of 30 °C background temperature, 80 % relative humidity, and a localized heat source intensity of 4.5 kW. The result of this paper can provide valuable information to develop PKAS for better thermal discomfort improvement and cooking pollutants control.

Numerical and experimental investigation of irradiance profiles on suspended particles in a flat disk photoreactor for hydrogen generation

Regarding sustainable energy alternatives, the present work evaluates hydrogen production using suspended particles exposed to an irradiance of 247 W/m2. A 1.0 L flat disk photoreactor (FDP) was designed for evaluating agitation speeds of 100, 175, and 250 RPM, and particle concentrations of 0.5, 1.0, and 2.0 g/L. Through CFD-assisted, a non-conformal meshing of 551,000 polyhedral elements was created, coupling Volume of Fluids, Discrete Particle Modelling, and Discrete Ordinates Model methods. Transient simulation shows a maximum particle homogenization of 84 % at 0.5 g/L and 250 RPM, and a maximum average exposure profile of 140 W/m2 for 27% of the particles with an initial loading of 1.0 g/L at 250 RPM.Effective concentration in the FDP was measured, determining an accuracy of 84.35% and 71.32%, respectively, concerning the model used in the simulation. It is concluded that the FDP developed provides good semiconductor behavior for an effective hydrogen production process.

Flatbread baking process under time-varying input power in a home-scale electric oven: 3D CFD simulation with experimental validation

This study investigates the flatbread baking process in a home-scale electric oven by developing a three-dimensional transient numerical model using the finite volume method along with the discrete ordinates (DO) model, evaporation–condensation mechanism, and realizable k-ε model for the turbulent regime through the oven chamber. The validity of the proposed numerical model has been examined through a comparison with experimental data provided in this study, considering both scenarios with and without bread in the oven, where good agreement is observed between the numerical and experimental findings. Using the validated model, a qualitative and quantitative analysis is performed to study the flatbread baking process, focusing on temperature distribution within the oven and the bread as well as the degree of starch gelatinization during the baking process. The consideration of input power patterns is crucial in terms of both energy consumption and bread quality, making it imperative for electric oven designers. Consequently, under a fixed energy consumption of the oven, various time-varying input powers are employed to assess the bread baking process. For this purpose, six different scenarios are designed including constant elements power, linear/stepwise increase/decrease in elements power, and ON/OFF modes with constant power. The results demonstrate that employing time-varying input power profiles characterized by linear and stepwise decrease yields superior performance to control the baking process and quality of bread. However, preheating the oven prior to dough baking could potentially mitigate the impact of the input power profile type on the resulting final product.

Directly irradiated liquid metal film in an ultra-high temperature solar cavity receiver. Part 2: Coupled CFD and radiation analysis

A novel solar cavity receiver was proposed in Part 1 to facilitate operation at ultra-high temperatures (>1300 K). The concept featured enclosing a directly irradiated liquid metal film inside a window-sealed cavity containing an inert protective fluid. The receiver’s technical performance was evaluated using a quasi-steady-state analysis based on various assumptions, which were used to enable analytical modelling of the involved energy transfer mechanisms. This paper describes a Computational Fluid Dynamics (CFD) solution developed to verify the conclusions of Part 1 and furtherly investigate the technical performance of the proposed receiver. The solution combined the Volume Of Fluid (VOF) and Discrete Ordinates Model (DOM) methods to simulate the volumetric radiation absorption by the liquid metal film while accounted for the transient flow developments of the gravity-driven film and buoyancy-driven cavity fluid. Analytical models were verified, showing improved performance for the absorptive cavity configuration. Film flow disintegration was mitigated by using surface corrugations, which were found to significantly influence the fluid dynamics and heat transfer performance of the receiver. Finally, a steady-state thermal analysis was presented for the proposed ceramic window, which indicated that active cooling is indispensable for protecting the window against thermo-mechanical fatigue.

Investigation of Thermal Radiation, Atomization Air, and Fuel Temperature Effects on Liquid Fuel Combustion

Abstract The purpose of the present study is to investigate the effects of radiative heat transfer, atomization air temperature and mass flowrate, and fuel initial temperature on liquid diesel fuel (C16H34) combustion. Fuel is injected by an airblast atomizer inside a model cylindrical combustion chamber. Geometry of the airblast atomizer is modeled in detail so that its impacts on droplet breakup and flow formation are accurately considered. Evaporating fuel spray is simulated by the discrete phase model based on the Eulerian–Lagrangian approach. Turbulent viscosity is numerically computed by the realizable k–ɛ turbulence model while the discrete ordinates model and the steady flamelet model are applied for modeling the radiative heat transfer and combustion, respectively. NO species concentrations are achieved using post-processing. It turns out that neglecting thermal radiation in well-atomized spray combustion only affects high-temperature zones by increasing the axial temperature values of the mixture by almost 8%. Thermal radiation has an imperative effect on producing NO species. Without considering thermal radiation, axial NO concentration becomes almost doubled. Augmentation in mass flowrate and temperature values of atomization air enhances spray formation and combustion efficiency by increasing the evaporation rate. Changing the fuel temperature from 300 K to 325 K rises the total temperature at the end of the centerline of the model combustion chamber by 9.8%. It is shown that increasing the fuel’s initial temperature is not a suitable choice compared to enhancing the temperature and mass flowrate of the atomization air.

A dual-solver CFD model for conjugate heat transfer in continuous thermal processing

High temperature heat treatment of powders is a common operation in the manufacturing of a range of commercial products. Often, powders are heated or cooled in discrete quantities while being conveyed through a continuous furnace or oven, where a certain temperature–time profile is required for product quality reasons. For powders that are contained and conveyed in oven-ware (saggars), heat-transfer occurs between the surrounding gas phase and the powder material and oven-ware, as well as between oven ware that is vertically stacked.The large physical size and long transit times through typical industrial furnaces (up to 40 m length) means that a full transient CFD solution for both gas and solid phases is computationally very expensive . In this study, a novel CFD simulation model is developed for conjugate heat transfer in the cooling section at the outlet of a continuous furnace. A particular novel feature in this model is the inclusion of heat conduction in multiple solid domains. A dual-solver approach enables the convective and radiant heat-transfer processes in the gas phase are modelled using a steady-state conjugate solver, while the heat conduction processes within the powders and saggars are modelled using a time-dependent conjugate solver that solves for heat conduction only. Using only steady-state solution for the gas phase enables a “snap-shot” of the thermal performance of the system to be generated in a reasonable time frame, which has practical implications for modelling of large-scale industrial equipment. In the “dual-solver” approach, heat fluxes at solid boundaries from the steady-state model are applied as boundary conditions to the transient solver, while the temperature field resulting from the solution of the transient solver is then applied to the steady-state model. Radiative cooling effects are accounted for using a discrete-ordinates model.

Comparative, numerical, and experimental study of the influence of infrared radiation on a radiative-convective drying system for kaolin clay

This study investigates the effect of radiation intensity on the drying of kaolin clay using a redesigned radiative-convective dryer set. The convective and hybrid drying curves are evaluated, and the radiant system is characterized through numerical and experimental analysis of the view factor profile and radiation contour by discrete ordinates model (DOM). The results demonstrate that radiation intensity and air velocity have a greater impact on the drying process than the air temperature. Notably, the air velocity is particularly influential at 2 m/s. A multivariate linear regression model is developed to represent the relationship between these variables with an R2 coefficient of determination of 82%. Under optimal hybrid drying conditions (air velocity: 2 m/s, air temperature: 40 °C, radiation intensity: 6.8 kW/m2), the mass flux is 15.1 times higher compared to convective drying conditions. Additionally, the discrete ordinates model accurately captures the behavior of radiation distribution in the 2D study, highlighting the need for further investigation in 3D to address magnitude of radiation deviations. These findings have significant implications for optimizing the drying process of kaolin clay and provide insights for the design of more efficient drying systems, as well as suggesting further research on the simulation and simplification of phenomena involving radiation heat transfer.

Investigation on the flow and heat transfer characteristics in a flame deflector with different water injection schemes

The thermal–hydraulic performance of flame deflector in a reduced-scale rocket engine testing platform with different water spray schemes is analyzed. The standard k-ε turbulent model and Eddy-Dissipation Concept (EDC) model are applied to solve the characteristic of the flow and combustion and the discrete ordinates (DO) model is adopted to simulate the thermal radiation. Model validation shows that the predicted results are in good agreement with the experimental data. In addition, the flow and temperature field of the exhaust gas impinging on the flame deflector under different water injection location, mass flow rate, hydrogen ratio and vertical panel height are numerically investigated. The results reveal that the scheme of centre water spray performs better than other schemes in terms of maximum and area-averaged temperatures. In terms of the flow performance, the case of annulus water spray performs best, followed by centre water spray and bottom water spray worst. With the increase of hydrogen ratio, the reburning of hydrogen results in the amplification of the high-temperature region in the flame deflector. The temperature on the bottom surface decreases gradually but the temperature on the vertical panel increases with the increase of the vertical panel height.

Construction of digital twin of the space furnace based on thermal simulation and data-driven thermophysical parameter identification technology

This study aims to demonstrate the construction of a simulation-based digital twin of a space furnace. During simulation processes, uncertainties in the results can arise from variations in parameter inputs and the utilization of different simulation models. Moreover, simulating complex models often demands substantial computational resources. To effectively achieve the desired digital twin effect, it is crucial to employ specific measures that address these challenges. In this paper, we propose a layered meshing strategy that aims to strike a balance between simulation accuracy and computational costs. By implementing this strategy, we can optimize the mesh design and achieve accurate results while efficiently managing computational resources. The performance of the meshing strategy is evaluated based on three indices: orthogonal quality, skewness, and aspect ratio. To enhance the repeatability of simulation results, we employ two key methods: model selection and thermophysical parameter identification. Laminar and discrete ordinate (DO) models are selected by comparing simulation results from different model combinations. A data-driven method is proposed to identify the thermophysical parameters when prior knowledge is lacking. To assess the validity of the proposed method, simulation results are compared with state-of-art methods. Results show satisfactory agreement between measured temperatures and simulated temperatures, with the relative error being approximately 1% at the temperature control thermocouples. The proposed thermophysical identification method achieves equivalent or better error performance compared to cumbersome manual adjustment and instrument measurement methods, which reduces experimental risks and costs.