CFD Software Package Research Articles

Computational investigation of cross flow heat exchanger: A study for performance enhancement using spherical dimples on fin surface

Performance improvement of a heat exchanger is a vast topic for research work right now. This paper presents a numerical analysis of cross flow heat exchanger using CFD software package ANSYS FLUENT. To improve the performance of a traditional smooth fined heat exchanger, dimples are used on the fin surfaces. A cross flow heat exchanger with spherical dimples on the surfaces of the fins was modelled and effect of dimples on the performance of the heat exchanger was numerically investigated. Numerical investigations were carried out for different dimple depths such as 3 mm, 4 mm, 5 mm, 5.5 mm dimples on different positions such as on one side, on both side; and different number of dimples such as 32, 26, 20. Boundary conditions were considered as constant tube outer surface temperature, Reynolds number of 3553, inlet air temperature Ti = 299.45 K. Considering balance between heat transfer enhancement and pressure drop, performance evaluation criterion (PEC) was estimated to observe the optimal result. PEC value greater than 1 means there is better performance in consideration of both heat transfer rate and frictional loss. The case of 26 dimples on both sides of fin with 5.5 mm dimple depth provides highest 7.33 % increases of Nusselt number compared to smooth fin. The maximum PEC value 1.034 was found for the case of 32 dimples on both side of fin with 3 mm dimple depth. From the PEC analysis, it was observed that the case of 32 dimples on both sides of the fin with 3 mm dimple depth is the optimum case among all other cases with 5.71 % higher Nu and 6.75 % higher friction factor than smooth fin. To compare the heat exchanger performance, temperature effectiveness has also been evaluated. The case of 32 dimples and 26 dimples on both side of fin with 5.5 mm dimple depth have same and highest value of temperature effectiveness which is 11.45 %, where that value for smooth fin is 10.16 %. Furthermore, the results have been analyzed with the variation of Reynolds numbers.

Hydrodynamic interaction between two polygonal cylinders in uniform potential flow

The analytical solution for uniform potential flow around two similar or dissimilar polygonal cylinders is obtained by using complex potential function for a doublet trapped in an annulus. The annulus of two circles is mapped conformally to the pair of polygonal cylinders by unique combination of bilinear and hypotrochoidal transformation and mathematical formulas to get velocity, pressure and hydrodynamic force distribution around two polygonal cylinders are presented. The effects of center distance between the cylinders, shape, orientation and corner radii of cylinders, and flow angle on the hydrodynamic interaction between the cylinders are also investigated and presented. The comparison of some of the numerical results obtained using present method is done with the results obtained from commercial CFD software package and results from literature.

Construction of pressure characteristics of a centrifugal radial fan using ANSYS CFX software package

Purpose. Improve the design and pressure characteristics of the centrifugal radial fan (CRF), reduce costs and design time by using modern design methods. Methods. Analytical study of the energy characteristics of the CRF using CFD software packages. Three-dimensional modeling of the flow of air in the flow part of the fan. Results. The paper describes the peculiarities of construction of the pressure characteristic of a centrifugal radial fan using the ANSYS CFX program. Numerical simulation of the flow was carried out to improve the initial indicators at the preliminary stage of the design of the CRF. This approach allows reducing costs and design time compared to the experimental approach and provides an opportunity to improve and analyze the performance of the fan and its design without manufacturing it. The use of a calculation complex of programs for the justification and analysis of the design results provides an opportunity to see the picture of the pressure distribution along the flow part, the field of velocity vectors and the movement of the air flow. By means of numerical modeling of the spatial air flow in the flow part of the fan, choosing the SST-turbulence model, the regularity of the change in the pressure characteristic of the fan was the distribution of velocities and pressures in different elements of the air conditioning system, at different values of the mass flow of air, was determined. An analysis of the change in total and static pressure in the flow part of the CRF was performed: in the stator – an inlet nozzle, in the rotor – a closed type impeller, and in the stator – made in the form of a snail. The question of the dependence of the total and static efficiency on the mass flow rate of the fan is also considered. Conclutions 1. Studies of the process of construction of the pressure characteristic of the CRF showed that the proposed approach allows you to reliably estimate the parameters of the fan’s operating modes, determine the main features of the change in determined. As a result of the calculation, efficiency and the distribution of full and static pressure in the elements of the flow part for its further improvement. 2. A distinctive feature of the proposed method of constructing the pressure characteristic is that in the early stages it is possible to predict the hydrodynamic parameters of the flow part of the designed fan without creating its solid-state model. And based on the results of a numerical study of the spatial air flow, it is possible to quantitatively and qualitatively analyze the elements of the flow part of the fan and specify their geometric dimensions for further calculation based on average parameters. 3. The ANSYS 19.0 CFX software complex allows you to immediately display changes in the design of fan assemblies and obtain the results of a numerical study of the spatial air flow in the flow part of the fan. Using the proposed graphic materials, it is possible to visually observe the processes taking place in the flow part of the CRF. The possibility of numerical calculation of the parameters of interest is also shown. 4. The creation of a real CRF to evaluate its performance requires significant funding and is time- consuming, while the use of CFD is fast and cost- effective. The ANSYS 19.0 CFX software package makes it possible to visually present a picture of the behavior of a wide range of process parameters that occur in the flow part of the fan and to show their relationship with the features of the geometry and dimensions of the fan. Keywords: total pressure, static pressure, nozzle, impeller, volute, CFD, mass flow, total efficiency, static efficiency.

Mathematical and CFD methods for prediction of thermal pollution caused by thermal power plant

Wastewaters from power plants is a major concern for environmental protection. After the water is used in thermal power plant, the heated effluent is again discharged in the same water body from where it is taken. This not only disturbs the aquatic life but also affects the balance of the ecosystem. This paper presents the background of the thermal pollution, modelling approach and analysis methods for prediction of thermal pollution. A 2-D model of Sava River is discussed. The thermal power plant Nikola Tesla B was considered. Analysis of thermal discharge into the Sava River for the twelve-year period has been carried out. It was done a comparative analysis of the results obtained using mathematical (Electricity of France ? EDF) method and numerical analysis using the CFD software package ANSYS FLUENT. A comparison of these two methods was made in order to show that it is possible to predict thermal pollution precisely and that it is possible to apply these methods in the design of industrial plants and not only in large thermal power plants. Finally, the results showed the matching of the obtained values at greater distances from the water outlet of the thermal power plant.

Substrate Characteristics of Multiple Arrays of Turbulent Swirling Impinging Jets

This research investigates the flow aspects and thermal behavior of multiple air jet impingements on a flat plate through two different geometrical arrangements. A variety of flow conditions and geometrical parameters are considered including Reynolds number, swirl number, impingement distance, and jet-to-jet separation. A numerical approach is adopted to conduct the analysis using the SST k-ω turbulence model in the commercial CFD software package ANSYS Fluent v17. Results reveal that the static pressure is uniformly distributed on the impingement surface for the higher nozzle-to-surface distance at a strong swirl flow, while for no-swirl and medium-swirl configurations, the static pressure is accumulated at the stagnation regions. A lower impingement distance ameliorates the cooling performance while a higher impingement distance accelerates the consistency in temperature distribution. Moreover, the staggered nozzle arrangement is found superior in terms of generating integrity in thermal cooling. Overall, the pressure coefficient enhances up to 126% for medium swirl (S = 0.3) and 67% for high swirl (S = 0.75) cases, and in terms of Reynolds number (Re), the pressure coefficient decreases by 12% and 15% for Re = 24600 and 35000, respectively, compared to Re = 11600. Besides, the average Nusselt number amplifies by 8% and 17% for medium (S = 0.3) and high swirl (S = 0.75) flow, respectively, while compared to Re = 11600, the average Nusselt number raises by 58% and 98% for Re = 24600, and 35000, respectively. The eddy viscosity increases strongly with the growth of swirl intensity, while a monotonous vorticity distribution is achieved at high swirl conditions.

Numerical Modeling of Electric Discharges Generated in Supersonic Flows

A numerical solver is developed for the modeling of electric discharges in high-speed flows. For the formulation of the physicochemical model, common electric discharge modeling approaches are combined with detailed models for nonequilibrium aerothermodynamics and finite-rate chemical kinetics. The physicochemical model is based on the single-fluid assumption and takes into account the thermal and chemical nonequilibria in the gas mixture. For the numerical implementation, the finite-volume-based open-source CFD software package OpenFOAM is used. The verification of the calculation models for thermodynamic and transport properties as well as finite-rate chemical kinetics is carried out by means of one-dimensional simulations. The first validation of the solver is carried out by means of a three-dimensional simulation of an electric discharge with a constant input power of 10 kW generated on the surface of a wedge in a supersonic nitrogen flow. The numerically obtained results are compared with corresponding experimental measurements and theoretical calculations and show a fair agreement. The numerically calculated maximum temperature values, for example, are 20–40% above the measured values. However, it should be noted that the experimentally obtained values represent a spatial integration over the entire measurement volume and therefore do not indicate maximum temperature values.

Epistemic uncertainty in URANS based CFD analysis of buoyancy driven flows—Comparison of URANS and LES

The containment is the last barrier to prevent the release of radioactive materials into the environment in case of a severe reactor accident. Thus, it is important to understand the flow and transport processes of combustible gases and to develop strategies to maintain the integrity of the containment. A holistic OpenFOAM-based CFD software package, containmentFOAM, is developed for containment analysis. During the validation of the code with regard to free convection flows and mixing processes, it became apparent that the simulation results are fairly sensitive to the definition of initial and boundary conditions, which are often not precisely known from the experiment. Therefore, establishing the validity of the models is impossible without a quantification of uncertainties.Generally, the uncertainty is categorized in two types, namely aleatoric and epistemic uncertainties. The first exhibits stochastic variations around the exact value. The latter has two possible effects on the uncertainty quantification: first a different sensitivity of the model to the input variation and second a bias to the exact value. Both effects can affect the significance of an aleatoric uncertainty quantification. The epistemic uncertainty originating from URANS turbulence modelling is investigated in this study by means of a direct comparison with the results obtained by LES, assuming that LES turbulence closures have smaller epistemic uncertainty. For a buoyancy driven natural circulation flow as well as a superimposed mixing process, both epistemic effects of the URANS approach are identified in terms of different sensitivities with respect to a variation of uncertain input parameters and the deviations of the URANS output variation ranges to those of LES. Nevertheless, the analysis of uncertainty bands derived on the basis of the most relevant parameter revealed that these epistemic effects ultimately result in a negligible effect on the aleatoric uncertainty quantification conducted with URANS.

Investigation on Shell and Tube Heat Exchanger by Using CFD

In this study, a detailed technique is built to examine the effectiveness of a shell and tube heat exchanger (STHE) with 35% baffle cuts (Bc) and variable numbers of baffles. Water was used as the working fluid in CFD simulations of a single pass and single tube heat exchanger. For this simulation investigation, a counterflow approach is used. The commercial CFD software package ANSYS-Fluent was utilized for computational analysis of STHE, and distribution of temperature was obtained due to the usage of copper and aluminum materials. In this research, the shell and tube heat exchanger was studied with the number of baffles of four, and six pieces by varying the mass flow rate value which is 0.5,0.8, and 0.9. From this research, it was found that the highest total heat transfer rate and highest heat transfer coefficient is produced by copper with Six baffles at 0.9 mass flow rate.

MODELING OF HEAT EXCHANGE PROCESSES IN THE TECHNOLOGICAL SYSTEM FOR THE RECYCLING OF METALLIC TUNGSTEN RODS

A computational experiment was carried out to study heat exchange processes. They flow in the installation for the production of metal powders, by spraying tungsten rods. This unit uses a special cooling system. The thermophysical problem is solved by one of the numerous methods of mathematical modeling of heat transfer processes. The finite element method was used, which is implemented in the CFD software package. The design and principle of operation of the spindle unit of the installation for sputtering tungsten rods are analyzed. It is represented by the object of mathematical modeling of heat transfer processes. The temperature distributions in the characteristic studied working areas of the parts of the installation units are obtained. Based on the simulation results in the CFD software package, the calculation results were analyzed. The results showed the high efficiency of the developed cooling system for the installation for spraying metal powders.

ANSYS CFX STUDY OF AERODYNAMIC CHARACTERISTICS DURING BLADE PROFILE ROTATION

Currently, wind energy is one of the most developing areas, which is primarily due to the absence of emissions of harmful substances into the atmosphere. Wind power allows providing electricity to remote areas, where fuel delivery, as well as the construction of thermal power plants is laborious and expensive. The effective development of wind turbines should solve the following tasks: the creation of the necessary driving force and the possibility of using a high coefficient of wind energy, which does not contradict the maintenance of the ecological balance of the territory. An electric generator for a household wind turbine must provide electricity in a wide range of rotation speeds and be able to work independently without automation and external energy sources. The study of the numerical implementation of the method of aerodynamic analysis of the wind turbine blade in rotational motion in the ANSYS CFD software package is by far the most promising and dynamically developing direction in the field of aerodynamics calculations. The results of approbation of the mixed calculation method using a dynamically variable and stationary finite-volume mesh are presented. The use of a mixed design scheme allows for calculations of wind turbines inside the building, while it becomes possible to minimize the required power for the study.

Numerical study of the dam-break waves and Favre waves down sloped wet rigid-bed at laboratory scale

The bed slope and the tailwater depth are two important ones among the factors that affect the propagation of the dam-break flood and Favre waves. Most previous studies have only focused on the macroscopic characteristics of the dam-break flows or Favre waves under the condition of horizontal bed, rather than the internal movement characteristics in sloped channel. The present study applies two numerical models, namely, large eddy simulation (LES) and shallow water equations (SWEs) models embedded in the CFD software package FLOW-3D to analyze the internal movement characteristics of the dam-break flows and Favre waves, such as water level, the velocity distribution, the fluid particles acceleration and the bed shear stress, under the different bed slopes and water depth ratios. The results under the conditions considered in this study show that there is a flow state transition in the flow evolution for the steep bed slope even in water depth ratio α = 0.1 (α is the ratio of the tailwater depth to the reservoir water depth). The flow state transition shows that the wavefront changes from a breaking state to undular. Such flow transition is not observed for the horizontal slope and mild bed slope. The existence of the Favre waves leads to a significant increase of the vertical velocity and the vertical acceleration. In this situation, the SWEs model has poor prediction. Analysis reveals that the variation of the maximum bed shear stress is affected by both the bed slope and tailwater depth. Under the same bed slope (e.g., S0 = 0.02), the maximum bed shear stress position develops downstream of the dam when α = 0.1, while it develops towards the end of the reservoir when α = 0.7. For the same water depth ratio (e.g., α = 0.7), the maximum bed shear stress position always locates within the reservoir at S0 = 0.02, while it appears in the downstream of the dam for S0 = 0 and 0.003 after the flow evolves for a while. The comparison between the numerical simulation and experimental measurements shows that the LES model can predict the internal movement characteristics with satisfactory accuracy. This study improves the understanding of the effect of both the bed slope and the tailwater depth on the internal movement characteristics of the dam-break flows and Favre waves, which also provides a valuable reference for determining the flood embankment height and designing the channel bed anti-scouring facility.

Ligand and precatalyst offerings expand

The bed slope and the tailwater depth are two important ones among the factors that affect the propagation of the dam-break flood and Favre waves. Most previous studies have only focused on the macroscopic characteristics of the dam-break flows or Favre waves under the condition of horizontal bed, rather than the internal movement characteristics in sloped channel. The present study applies two numerical models, namely, large eddy simulation (LES) and shallow water equations (SWEs) models embedded in the CFD software package FLOW-3D to analyze the internal movement characteristics of the dam-break flows and Favre waves, such as water level, the velocity distribution, the fluid particles acceleration and the bed shear stress, under the different bed slopes and water depth ratios. The results under the conditions considered in this study show that there is a flow state transition in the flow evolution for the steep bed slope even in water depth ratio α = 0.1 (α is the ratio of the tailwater depth to the reservoir water depth). The flow state transition shows that the wavefront changes from a breaking state to undular. Such flow transition is not observed for the horizontal slope and mild bed slope. The existence of the Favre waves leads to a significant increase of the vertical velocity and the vertical acceleration. In this situation, the SWEs model has poor prediction. Analysis reveals that the variation of the maximum bed shear stress is affected by both the bed slope and tailwater depth. Under the same bed slope (e.g., S0 = 0.02), the maximum bed shear stress position develops downstream of the dam when α = 0.1, while it develops towards the end of the reservoir when α = 0.7. For the same water depth ratio (e.g., α = 0.7), the maximum bed shear stress position always locates within the reservoir at S0 = 0.02, while it appears in the downstream of the dam for S0 = 0 and 0.003 after the flow evolves for a while. The comparison between the numerical simulation and experimental measurements shows that the LES model can predict the internal movement characteristics with satisfactory accuracy. This study improves the understanding of the effect of both the bed slope and the tailwater depth on the internal movement characteristics of the dam-break flows and Favre waves, which also provides a valuable reference for determining the flood embankment height and designing the channel bed anti-scouring facility.

CFD Analysis into the Drag Characteristics of Trimaran Vessel: Comparative Study between Standard NPL 4a and the use of Axe-Bow

Recently, there has been an increased demand for multihull vessels for military and commercial applications. This demand for multihull vessels is to balance speed with payload requirements. One such hull form is the trimaran. This research conducted a CFD analysis of resistance for trimaran hull forms as a parameter range of practical hull forms is established round bilge trimaran hull forms based on the NPL systematic series and Axe-Bow Modification at the main hull. The resistances of trimaran hull forms are, therefore, estimated by using ANSYS CFX, a commercial CFD software package. Trimaran model was analysed on variation of main hull and side independently, S/L = 0.3 and S/L = 0.4 at Fr = 0.15, 0.2, 0.25, 0.3, 0.4 and 0.5. The results showed that the trimaran ship with the Axe-Bow modification showed better results when compared to the NPL Hull, with an average value of 26.6%. This shows a positive influence with the use of Axe-Bow on the modification of the NPL Hull in the trimaran ship configuration.

Characterizing combustion of a hybrid rocket using laser absorption spectroscopy

The combustion of an oxygen/paraffin hybrid rocket motor was experimentally characterized. Firing tests were conducted for different oxidizer mass fluxes ranging from 2.47 to 3.40 g/ (cm2·s). Variations in temperature and H2O partial pressure at the nozzle exit were diagnosed using mid-infrared tunable diode laser absorption spectroscopy (TDLAS) based on H2O absorption near 2.5 μm. Three H2O absorption lines were simultaneously covered by only one distributed feedback (DFB) laser using scanned-wavelength direct absorption (DA) mode with 2.0 kHz repetition rate. Measurement uncertainty was analyzed in detail considering line-strength uncertainty and Voigt fitting residuals. A two-dimensional (2D) model of the nozzle was constructed using the ANSYS FLUENT CFD software package. The combustion efficiency of the hybrid rocket motor was evaluated from the perspectives of chemical reaction and heat release, respectively, based on TDLAS results and CFD simulations. The effectiveness of the evaluation was validated by comparing its results with characteristic velocity (C*)-based combustion efficiency. Finally, comparisons of combustion efficiencies among different cases show that increasing the oxidizer mass flux or oxidizer-to-fuel ratio improves the combustion efficiency of the hybrid rocket motor under our experimental conditions.

Моделирование системы распределения воздуха пассажирского самолета

The paper considers an air distribution system for a pressurized cabin in a civil aircraft. We propose a method for simulating this system that involves developing a one-dimensional model based on hydraulic computation results for the three-dimensional geometry of the distribution system structure. This approach makes it possible to recompute air distribution in large branching systems relatively quickly and with sufficient accuracy when making changes to their design. The advantages of this method include lower computing costs and lower labour intensity compared to using a modern CFD software package to simulate a full three-dimensional flow in the distribution system structure. The paper describes the operation of the air distribution system prototype and presents the schematic diagram and the functional flow block diagram of the system. We show how to use three-dimensional simulation to determine the discharge characteristics of system pipelines. We present the numerical model constructed for the system and display the capabilities of this model in static and dynamic simulation modes. We analysed the simulation results and confirmed the possibility of using the method proposed for engineering computations. We validated the numerical model using experimental investigation results obtained by means of an empirical test bench simulating the air distribution system prototype.

Investigate Impact Force of Dam-Break Flow against Structures by Both 2D and 3D Numerical Simulations

The aim of this paper was to investigate the ability of some 2D and 3D numerical models to simulate flood waves in the presence of an isolated building or building array in an inundated area. Firstly, the proposed 2D numerical model was based on the finite-volume method (FVM) to solve 2D shallow-water equations (2D-SWEs) on structured mesh. The flux-difference splitting method (FDS) was utilized to obtain an exact mass balance while the Roe scheme was invoked to approximate Riemann problems. Secondly, the 3D commercially available CFD software package was selected, which contained a Flow 3D model with two turbulent models: Reynolds-averaged Navier-Stokes (RANs) with a renormalized group (RNG) and a large-eddy simulation (LES). The numerical results of an impact force on an obstruction due to a dam-break flow showed that a 3D solution was much better than a 2D one. By comparing the 3D numerical force results of an impact force acting on building arrays with the existence experimental data, the influence of velocity-induced force on a dynamic force was quantified by a function of the Froude number and the water depth of the incident wave. Furthermore, we investigated the effect of the initial water stage and dam-break width on the 3D-computed results of the peak value of force intensity.

Numerical modeling of an inductively coupled plasma torch using OpenFOAM

A customized code using the free and fully open-source CFD software package OpenFOAM was developed to simulate a two-dimensional axisymmetric model of an inductively coupled plasma torch. To efficiently calculate the high-frequency magnetic fields generated by the inductive coil, a technique based on the vector potential formulation of Maxwell’s equations was implemented using the block coupled matrix solver provided by the foam-extend toolbox. While the fluid equations for the inner torch region are solved under the assumption of a laminar flowing argon plasma under atmospheric pressure and local thermodynamic equilibrium conditions, the electromagnetic equations are solved on an overlapping mesh extended far outside the torch. Moreover, a novel technique for initializing the plasma solver by separately precomputing the velocity and temperature fields is presented. Using this approach our plasma solver can run in both steady-state and transient modes. The implementation has been validated by means of analytical methods, and the simulation results of the Tekna-PL50 plasma torch have been compared against literature data. The results obtained using the OpenFOAM code are in good agreement with those of the commercial CFD codes.

Computational modelling of the heat transfer through two-layer woven structure ensembles

The purpose of the present study was to investigate the heat transfer through a system of two consecutive textile layers with woven macrostructures by numerical simulation, using FLUENT CFD software package. A novel approach for modelling of the textile structure was applied, based on jet systems. The heat transfer through the systems of layers was studied for indoor conditions, simulating skin and indoor air temperature, as well as the effect of the convective cross flow around the human body. The results of the study showed that the heat transfer through a system of two layers is strongly influenced by the porosity and thickness of the fabrics, as well as their arrangement in the systems as an insulating barrier between the body and the environment.

Computational modelling of the heat transfer through two-layer woven structure ensembles

The purpose of the present study was to investigate the heat transfer through a system of two consecutive textile layers with woven macrostructures by numerical simulation, using FLUENT CFD software package. A novel approach for modelling of the textile structure was applied, based on jet systems. The heat transfer through the systems of layers was studied for indoor conditions, simulating skin and indoor air temperature, as well as the effect of the convective cross flow around the human body. The results of the study showed that the heat transfer through a system of two layers is strongly influenced by the porosity and thickness of the fabrics, as well as their arrangement in the systems as an insulating barrier between the body and the environment.

Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

This paper focuses on a two-dimensional CFD simulation of a downdraft gasifier and a pilot-scale experiment for verification using wood pellet fuel. The simulation work was carried out via the ANSYS-Fluent CFD software package with in-house coding via User Defined Function. Three gasification parameters were taken into account in the simulation and validation to achieve highly accurate results; namely, fuel consumption, temperature profile, and syngas composition. After verification of the developed model, the effects of aspect ratios on temperature and syngas composition were investigated. Results from simulation and experimental work indicated that the fuel consumption rate during the steady state gasification experiment was 1.750 ± 0.048 g/s. The average steady state temperature of the experiment was 1240.32 ± 14.20 K. In sum, the fuel consumption and temperature profile during gasification from modeling and experimentation show an error lower than 1.3%. Concentrations of CO, CO2, H2, and CH4 were 20.42 vol%, 15.09 vol%, 8.02 vol%, and 2.6 vol%, respectively, which are comparable to those of the experiment: 20.00 vol%, 15.48 vol%, 8.00 vol%, and 2.65 vol%. A high concentration of syngas is observed in the outer radial part of the reactor because of the resistive flow of the air inlet and the synthesis gas produced. The average temperatures during the steady state of the gasifier with aspect ratios (H/D) of 1.00, 1.38 (experiment), and 1.82 were 978.77 ± 11.60, 1256.46 ± 9.90, and 1368.94 ± 9.20 K, respectively. The 1.82 aspect ratio reactor has the smallest diameter, therefore the radiative heat transferred from the reactor wall affects the temperature in the reactor. Syngas compositions are comparable. Inverse relationships between the aspect ratios and the syngas LHV, (4.29–4.49 MJ/N m3), cold gas efficiency (29.66% to 31.00%), and carbon conversion (79.59% to 80.87%) are observed.