Gas Mass Flow Research Articles

Performance analysis of a novel gas-liquid separator with industrial application

This paper presents a novel gas-liquid separator characterized by its distinctive geometric design, capable of handling different volume fractions and mass flow rates. The separator's performance is comprehensively assessed across various gas volume fractions, bubble sizes, and mass flow rate fluctuations. The study reveals that variations in vapor volume fraction substantially affect both separation efficiency and pressure loss. An increase in vapor volume fraction from 0.1 to 0.5 leads to a 25% reduction in separation efficiency and a 3.3-fold decrease in pressure loss. In contrast, changes in mass flow rate exert a relatively minor influence on separation efficiency. Specifically, increasing the mass flow rate from 15 to 30 kg/s results in a mere 4% decrease in separation efficiency, whereas pressure loss increases by a factor of 3.2.Additionally, a reduction in bubble size from 1000 µm to 200 µm causes a 33% increase in pressure loss and a 14% decrease in separation efficiency. The incorporation of a meshpad in this design promotes the formation of a forced vortex, thereby enhancing the separation process.

Modeling of high-pressure transient gas-liquid flow in M-shaped jumpers of subsea gas production systems

Two-phase flow with low liquid loads is common in high-pressure natural gas offshore gathering and transmission pipelines. During gas production slowdowns or shutdowns, an accumulation of liquid in the lower sections of subsea pipelines may occur. This phenomenon is observed in jumpers that connect different units in deep-water subsea gas production facilities. The displacement of the accumulated liquid during production ramp-up induces temporal variations in pressure drop across the jumper and forces on its elbows, resulting in flow-induced vibrations (FIV) that pose potential risks to the structural integrity of the jumper. To bridge the gap between laboratory experiments and field conditions, transient 3D numerical simulations were conducted using the OpenFOAM software. These simulations facilitated the development of a mechanistic model to elucidate the factors contributing to increased pressure and forces during the liquid purging process. The study examined the influence of gas pressure level, pipe diameter, initially accumulated liquid amount, liquid properties, and gas mass flow rate on the transient pressure drop and the forces acting on the jumper's elbows. The critical gas production rate required for complete liquid removal of the accumulated liquid was determined, and scaling rules were proposed to predict the effects of gas pressure and pipe diameter on this critical value. The dominant frequencies of pressure and force fluctuations were identified, with low-pressure systems exhibiting frequencies associated with two-phase flow phenomena and high-pressure systems showing frequencies attributed to acoustic waves.

A study of particle motion in Kwerk-type twisted blades: Effect of configuration on particle mixing performance by CFD–DEM

Static mixers could promote the particle mixing in industries. Experimental and numerical investigations of particle mixing and flow characteristics in the riser with static mixers are carried out. The instantaneous microscopic characteristics and energy loss in Kwerk-type static mixer (K-KSM) are evaluated by Computational Fluid Dynamics coupled with Discrete Element Method (CFD–DEM). A more suitable calculation method is proposed, which utilizes particle coordinates and the coordination number of central particles to calculate the instantaneous mixing degree of particles (PK). The PK, Residence Time Distribution (RTD) and collision correlation are analyzed at different superficial gas velocities (Ug) and mass flow rates (Ms). The results show that the performance of K-KSM is superior to that of KSM under current conditions. Back mixing and aggregation phenomena are eliminated at Ug > 5 m/s and Ms < 1.73 g/s, and the recommended regimes are Ug ≥ 6.0 m/s and Ms < 1.5 g/s.

Part-load analysis and preliminary annual simulation of a constant inventory supercritical CO2 power plant for waste heat recovery in cement industry

The present work investigates the part-load performance of a MW-scale sCO2 power plant designed as waste heat recovery unit for an existing cement plant located in Czech Republic, in the framework of the H2020 funded project CO2OLHEAT. The study first presents the selected power plant configuration and then focuses on the evaluation of its part-load operation due to variation of flue gas mass flow rate and temperature. The range of flue gas conditions at the outlet of the upstream process is retrieved from a preliminary statistical analysis of historical trends obtained through the cement plant monitoring. The numerical model developed for this study aims at providing realistic results thanks to the adoption of turbomachinery performance maps provided by the turbomachinery manufacturer of the project. Moreover, heat exchangers have been modelled through a discretized approach which has been validated against manufacturer data, while piping inventory and pressure losses have been assessed through a preliminary sizing that considers the actual distances to be covered in the cement plant. Performance decay is estimated for the whole range of flue gas conditions, reporting the most significant power cycle parameters, and identifying the main causes of efficiency loss. The part-load analysis is carried out considering a constant CO2 inventory, in order to reduce the system complexity and capital cost and simplify plant operation. Results show that the operation entails minor variation of the compressors operative points in the whole range of operating conditions of the cement plant, avoiding the risk of anti-surge bypass activation. Moreover, the plant is able to work close to the nominal thermodynamic cycle efficiency (20.5 %–23.0 %) for most of the year and benefits from part-load operation in terms of overall performance. In the last part of the work, a preliminary techno-economic analysis of the plant is also presented to highlight the potential advantages of sCO2 technology for waste heat recovery applications. The results of the part-load performance of the plant are combined with the flue gases data obtained from the preliminary statistical analysis and the cement plant historical monitoring. An annual electricity production equal to 13′909.7 MWh is obtained, corresponding to 6560 equivalent hours and a system capacity factor of 74.9 %. The investment cost of each CO2OLHEAT plant component is estimated by means of cost correlations obtained from literature and the non-discounted payback time is computed as a function of the electricity selling price. The results show that, even considering electricity prices before 2022, the payback time of the CO2OLHEAT plant is estimated to be lower than 8 years, justifying the industrial interest in the proposed technology.

Physics-data fusion for digital metering of gas-liquid two-phase flow in oil nozzles

Oil well production metering is an important basis for assessing resource reserves and production capacity. Existing metering methods require high investment and involve significant implementation difficulties and high computational costs. A new method of multiphase flow metering method was proposed by combining the fluctuation of pressure drop and temperature difference generated after throttling through the oil nozzle. The throttling equation coupling differential pressure, flow rate and gas fraction was derived. By regulating the gas and liquid superficial velocity, we carried out the experimental test for true nozzle aperture of 10 mm in the loop system, covering various flow patterns. In addition, the deep neural network was constructed for inversion prediction of mass gas fraction. The proposed flow metering equation has an adaptable gas mass fraction range of 0 to 100%, unaffected by the variations in flow patterns, gas-liquid velocities, and system pressure changes. The metering errors of gas mass fraction and mass flow rate is below ±10%. The proposed metering method only relies on the existing temperature and pressure measurement system in the gathering and transportation system, and no additional measuring devices are required. It can be widely used in oil filed production to realize the virtual metering.

Off-design behaviors of a solar-powered HDH system for water and power cogeneration

A solar-powered humidification-dehumidification (HDH) desalination system offers flexible water and power cogeneration, promising in addressing energy crisis. However, the system’s operation frequently deviates from the on-design condition, making it crucial to study its off-design behaviors. This paper develops an off-design model to investigate the operation performance in response to variations in liquid–gas mass flow rate ratio (MFRR) and solar intensity. Furthermore, the heat and mass transfer mechanisms in humidifier and dehumidifier are inquired under specific conditions. The results exhibit that the system performance sensitivity to changes in the liquid–gas mass flow rate ratio and solar intensity aligns with the expectations under on-design conditions. The combined heat and mass transfer process weakens first and then strengthens from the bottom to the top in the humidifier, and vice versa in the dehumidifier. Notably, a higher freshwater flow rate enhances dehumidification efficiency, raising gained-output-ratio (GOR) by 7.13% and water production by 1.5%. Validation experiments confirm the off-design model’s accuracy and credibility, to offer methodological insights for the effective prediction of off-design behaviors.

Evaluating long-term operational data of a Very Large Crude Carrier: Assessing the diesel engines waste heat potential for integrating ORC systems

Given the spotlight on waste heat recovery (WHR) technologies for decarbonizing the shipping industry, critically assessing waste heat from propulsion and auxiliary engines using actual data is crucial for accurately predicting fuel and carbon savings. This paper addresses this by applying advanced data processing, considering voyage characteristics, and developing methods for mapping waste heat from main engine (ME) and diesel gensets (DGs) operations using long-term operational data from a Very Large Crude Carrier (VLCC) case study. Two methods predict unrecorded air mass flows by implementing heat balance: one using measured temperature values and the other estimating exhaust gas mass flow rates based on fuel oil consumption. Within the main objectives of this study is to examine the impacts of employing the exhaust gases of both ME and DGs to evaporate recuperative ORC working fluid on power output and vessel annual carbon savings, with the formed diesel engines operational profiles serving as inputs. Simulations show a power output of 530 kW using ME exhaust gases, increasing to 653 kW and 741 kW with DGs integration for R245fa and R1233zd(E) as the selected ORC working fluids, respectively. The proposed solutions can reduce annual CO2 emissions by 4 % to 7 %.

Maximizing Chlorobenzene Product Yield by Modifying The Benzene Chlorination Process

Chlorobenzene is extensively used in the manufacture of phenol, aniline, and DDT; as a solvent for paints; and as a heat transfer medium. It is also occasionally used in the dry-cleaning industry. With the many uses of chlorobenzene, its production must have high efficiency both in terms of energy and mass in order to obtain maximum profits. In this paper, we will explain how to maximize chlorobenzene product yield by modifying the benzene chlorination process. The process modification was carried out by adding one distillation column unit and one mixer unit. Meanwhile, to carry out sensitivity analysis, case study tools on chemical engineering software were used. Based on process modifications, an increase in chlorobenzene yield was obtained from 83% to 98%. The results of the case study indicate that the higher the benzene pressure entering the reactor, the lower the yield of the liquid product exiting the reactor. Meanwhile, the higher the ratio of benzene mass flow to chlorine gas mass flow, the higher the yield of the liquid product exiting the reactor. Copyright © 2024 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Precipitation and evaporation affecting landfill gas migration into passive methane oxidation biosystems: Models development and verification

Passive methane oxidation biosystems (PMOBs) are developed as an innovative and cost-effective solution to reduce methane (CH4) emissions from municipal solid waste landfills. A PMOB consists of a methane oxidation layer (MOL) and an underlying gas distribution layer (GDL). The length of unrestricted gas migration (LUGM) has been recently proposed as the design criterion for PMOBs where the LUGM is calculated as the horizontal length along the MOL-GDL interface with the volumetric gas content (θa) exceeding the threshold volumetric gas content (θa,occ). This paper examined water and gas migration within three PMOBs with different MOL-GDL interfaces subject to precipitation and evaporation using verified numerical models. The results show that the use of a single-phase flow model underestimates the LUGM values of the PMOB for heavy precipitation events, and a two-phase flow model should be used to calculate both the LUGM and the total gas mass flow rate into the MOL when designing PMOBs. Both zig-zag and trapezoidal MOL-GDL interfaces can redistribute the gas mass flow rate at the MOL-GDL interface, while the trapezoidal MOL-GDL interface slightly outperforms the zig-zag MOL-GDL interface for enhancing the total gas mass flow rate into the MOL when comparing with the planar MOL-GDL interface. The zig-zag and trapezoidal MOL-GDL interfaces allow gas migration in the upper part of each PMOB segment even when the lower part of each PMOB segment was filled with water, and thus have a potential to minimize hotspot formation.

Integration ammonia cracking process and co-firing of natural gas in combined cycle power plant: A thermodynamic analysis

The global energy sector is currently facing the dual challenges of meeting increasing energy demands while reducing greenhouse gas emissions. In this context, the utilization of ammonia (NH3) as a hydrogen (H2) carrier and its integration into power generation systems is gaining attention as a potential solution. This study presents a comprehensive thermodynamic analysis of the novel integration of an NH3 cracking process with a natural gas co-firing combined cycle power plant. Through the integration of the NH3 cracking process with the power plant, H2 can be transported more efficiently through NH3. The NH3–H2–N2 fuel mixture is produced through NH3 cracking, with a craking ratio of 52 % (48 % molar fraction of NH3), to ensure a similar laminar burning velocity to that of natural gas. Our analysis focuses on the efficiency implications and environmental impacts of incorporating NH3 as a sustainable energy source, particularly in terms of NOx emissions. The results demonstrate that by reducing the natural gas input, CO2 emissions can be significantly reduced. However, the decrease in exhaust gas mass flow rate limits its utilization in the steam turbine as part of a combined cycle, as a significant portion of the exhaust gas is utilized to crack NH3. Moreover, this study provides valuable insights into the feasibility and benefits of NH3 integration in power generation, thereby contributing to the ongoing discourse on sustainable energy solutions.

Study on multi-stage adjust mechanism of downhole stratification control tool for natural gas hydrate multi-gas combined production gas lift

Accurate control of natural gas flow and pressure is essential to achieving multi-gas combined production of the natural gas hydrates. In this study, a downhole stratification control tool for controlling natural gas flow rate and pressure with a multi-stage throttling structure was innovatively proposed. The multi-stage throttling structure combined an adjustable cage sleeve and a fixed nozzle. The numerical model of the internal flow field of the downhole stratification control tool was established. Through the computer fluid dynamics numerical simulation, the flow field change law inside the spool module of the downhole stratification control tool under different spool structures, different outlet pressures, and different spool openings was analyzed. Moreover, the spool module prototype was processed, and the indoor experiment of the spool's performance of reducing pressure and regulating production was carried out. The results show that the multi-stage throttling structure has the advantages of adjustable spool opening and moderate cooling range and the mass flow of gas inside the spool changes linearly with the opening of the spool. The spool module can accurately control the mass flow of natural gas under high-pressure conditions, and meet the needs of the downhole stratification control tool for accurate gas control.

Spatial assessment of pollutants concentration in air and soils impacted by industrial wastes in lagos state, Nigeria

The mega city of Lagos, Nigeria is plagued by various environmental issues, chief amongst them being environmental pollution induced by poor and disjointed urban industrial waste management practices. This study aimed to identify and quantify the types of urban industrial waste generated in Lagos State. The State plays host to the largest population base in Nigeria with over twenty million people. The study adopted a quasi-experimental design. Soil, industrial waste generation and pollutant levels were determined with the aid of a thermal mass gas flow meter. Industrial wastes were measured in situ using a weighting scale, while surface soil samples were collected at depths of 0–30 cm. Results show that 20% of the industrial waste generated in the metropolis was ignitable (possibility of spontaneous combustion). The results were thereafter compared with international standards on the permissible limits for various pollutants in air and soil of Lagos State. Ikorodu had the greatest contribution of industrial waste generated in Lagos, followed by Ikeja, Oshodi, Ojo/Alaba and Surulere. The implications of these results and findings is that a lot needs to be done in terms of appropriate legislation, enforcement and tracking of industrial waste generation in Lagos State for effective monitoring and implementation of management strategies.

Performance enhancement of high temperature fin-and-tube heat exchanger employing winglet combined vortex generators

The fin-and-tube heat exchanger (FTHE) has the advantages of high temperature resistance, compact structure and high efficiency, and has been regarded as the optimal choice for flue gas heat transfer. In this study, the novel winglet vortex generators (VGs) are proposed for the high temperature HTHE where the flue gas with the inlet temperature of 1233 K transfers heat to the water. The effects of the combined VGs and the winglet combined VGs on the flue gas thermal–hydraulic performances are numerically studied. Furthermore, three winglet shapes including the triangular, trapezoidal and rectangular are compared. Moreover, the variations of high temperature HTHE performances with the flue gas mass flow rate are investigated. Compared to the plain fins, the surface heat flux and pressure drop of the combined VGs fins are increase by 15.8 % and 78.9 %, respectively. The designed winglets in the wake region could further reduce the area of the “teardrops” after the tube. The rectangular winglet combined VGs are decided as the best structure, which could maximally increase the surface heat flux by 11.9 kW/m2 compared to the triangular winglet combined VGs, while the pressure drop is slightly increased. Compared to the plain fins, the Nu of the rectangular winglet combined VGs is maximally increased by 16.4 and the maximum hydrothermal performance factor (HTPF) is 1.14. The optimum flue gas mass flow rate is determined as 1 g/s for the designed structures. This work can provide valuable guidance for design and modification of the high temperature HTHEs.

Compact heat pipe heat exchanger for waste heat recovery within a low-temperature range

Heat pipe heat exchangers (HPHX) are attracting attention for being capable of effective heat exchange through phase change. Much waste heat is generated at low-temperature sources, but there has been a lack of research on this. Most previous studies focus on large HPHXs over 1 m in length. In the present study, a compact HPHX (185 × 70 × 140 mm3) with nine heat pipes was fabricated, and the potential for waste heat recovery (WHR) was investigated at low heat sources. Also, the thermal performance of the HPHX was compared with and without the fin of the heat pipe. Experiments were conducted by changing the hot-side gas temperatures (50, 75, 100, and 125 °C) and mass flow rates (0.03, 0.04, and 0.05 kg/s). The heat transfer rate and pressure loss had a linear relationship with the hot-side temperature and mass flow rate. Despite a low temperature 50 °C, more than 100 W of heat can be recovered using a compact HPHX. At least 1.8 times improved thermal performance was obtained in HPHX in which finned heat pipes were installed. These results are expected to serve as indicators for various applications that generate low-temperature waste heat, such as clothes dryers and kitchen hoods.

Predicting compressor mass flow rate using various machine learning approaches

Abstract A major focus of the present study is to construct high-fidelity models for predicting corrected mass flow rates based on the collected compressor map data. Both traditional machine learning research and modern deep learning techniques have been employed to obtain well-fitted regression models of compressor mass flow rate. As traditional machine learning methods, Multiple Linear Regression and Random Forest, are conducted on compressor maps for prediction of corrected mass flow rate. The time series-based deep learning models are able to capture the overall trend of a given input for specific map data. Therefore, a time series-based deep learning technique, namely Gated Recurrent Unit has been employed to improve regression results. Besides, the prediction capabilities of the models, results also show that the proposed models can be used for the development of dynamic aero-thermal mathematical models of gas turbine engines and mass flow rate models created for dynamic compressors in other disciplines.

PARAMETRIC EVALUATION OF HEAT RECOVERY IN A RECUPERATIVE HEAT EXCHANGER

As urban centers grow and environmental regulations become more stringent, the complexity of integral systems within vehicles, aircraft, and other urban essentials escalates. A pivotal response to this challenge involves achieving enhanced energy efficiency and environmental appeal while maintaining cost-effectiveness. In this context, mathematical modeling, coupled with simulation and optimization techniques, emerges as a pivotal tool. This approach yields favorable outcomes with modest initial investments, contrasting with the resource-intensive nature of purely experimental design. Amongst the fundamental components, heat exchangers find widespread use, facilitating thermal exchange between fluids across diverse applications. Consequently, meticulous design and parametric optimization of these devices to attain peak performance and optimal energy efficiency are imperative, aligning with evolving environmental and energy trends. The simulation of such systems operates within an expansive range of operational and geometric parameters. These encompass mass flow rates, line pressures, pipe diameters, and pipe placements. However, excessive parameter combinations can render optimization computationally infeasible, necessitating judicious simplifications. Striking a balance between precision and computational efficiency, reduced-order models present a valuable intermediary solution. These models, situated between low- and high-order methods, offer robust mathematical representations without significant precision compromises. Thus, reduced-order models, which constitute an intermediate approach when compared to low- and high-order methods, can be used as a mathematical modeling tool without a significant loss of precision in the results. The present work presents an optimization and parametric analysis of a recuperative heat exchanger using a reduced-order approach employing the volume element model (VEM) as a discretization method, which is capable of providing accurate results at low costs. computational. The Laws of Conservation of Mass and Energy are applied to volume elements in combination with empirical correlations in order to quantify the quantities of interest, such as the convection heat transfer coefficient and temperature distribution. A parametric analysis was performed in order to observe the behavior of entropy generation in order to find its minimum points. The mass flow of water varied from 0.001 kg/s to 0.0085 kg/s with the mass flow of hot gases and the mass flow rate of gas was held constant in three stages, namely: 0.14 kg/s; 0.2 kg/s; and 0.3 kg/s. The local minimum was obtained for each of the three gas mass flow rate considerations, 8.53 W/K, 8.78 W/K, and 9.20 W/K respectively.

Plasma emission spectroscopy and optical properties of reactive-sputtered silicon oxynitride films

Silicon oxynitride (SiO x N y ) thin films were synthesized via reactive direct current magnetron sputtering under different reactive gas mass flow ratios (O2:N2) and discharge powers. The process was monitored by optical emission spectroscopy (OES), while spectroscopic ellipsometry was used to characterize the optical properties of the thin films and deposition rates. In this work, the plasma generated under different deposition parameters is analyzed by monitoring the emission lines of different species (Si I, Ar I, O2, and N2) and these results are then correlated with the corresponding target poisoning process and the optical properties of the grown thin films. According to the spectral analysis, the emission lines proved to be sensitive to the synthesis process as it was possible to differentiate deposition variations when other parameters remained unchanged. Furthermore, similar plasma conditions determined via the emission of different species were found to produce consistent thin film optical properties and vice versa. OES showed to be an effective method of monitoring and controlling the deposition of SiO x N y thin films with specific compositions.

Research on Off-Design Characteristics and Control of an Innovative S-CO2 Power Cycle Driven by the Flue Gas Waste Heat

Recently, supercritical CO2 (S-CO2) has been extensively applied for the recovery of waste heat from flue gas. Although various cycle configurations have been proposed, existing studies predominantly focus on the steady analysis and optimization of different S-CO2 structures under design conditions, and there is a noticeable deficiency in off-design research, especially for the innovative S-CO2 cycles. Thus, in this work aimed at the proposed novel S-CO2 power cycle, off-design characteristics and corresponding control strategies are investigated for the waste heat recovery. Based on the design parameters of the S-CO2 cycle, structural dimensions of printed circuit heat exchangers (PCHEs) and shell-and-tube heat exchangers are determined, and design values of turbines and compressors are specified. On this basis, off-design models for these key components are formulated. By manipulating variables such as cooling water inlet temperature, cooling water mass flow rate, flue gas inlet temperature and flue gas mass flow rate, cycle performances of the system are analyzed under off-design conditions. The simulation results show that when the inlet temperature and the mass flow rate of cooling water vary separately, the thermal efficiency both can reach the maximum value of 28.43% at the design point. For the changes in heat source parameters, the optimum point is slightly deviated from the design condition. Amidst the fluctuations in flue gas inlet temperature, the thermal efficiency optimizes to a peak of 28.56% at 530 °C. In the case of variation in the flue gas mass flow rate, the highest thermal efficiency 28.75% can be obtained. Furthermore, to maintain the efficient and stable operation of the S-CO2 power cycle, the corresponding control strategy of the cooling water mass flow rate is proposed for the cooling water inlet temperature variation. Generally, when the inlet temperature of cooling water increases from 23 °C to 27 °C, the cooling water mass flow should increase from 82.3% to 132.7% of the design value to keep the system running as much as possible at design conditions.

The extent and power of ‘maintenance mode’ feedback in MaNGA AGN

ABSTRACT We study the ionized gas kinematics of 293 Active Galactic Nucleus (AGN) hosts as compared to that of 485 control galaxies from the MaNGA–SDSS survey using measurements of the [O iii]$\lambda$5007 Å emission-line profiles, presenting flux, velocity, and W$_{80}$ maps. In 45 per cent of the AGN, a broad component was needed to fit the line profiles wings within the inner few kpc, that we have identified with an outflow. But in most AGN, the profiles are broader than that of their controls over a much more extended region, identified as the ‘kinematically disturbed regions’ (KDRs). We find a positive correlation between the mean $\langle$W$_{80}\rangle$ and L[O iii], supporting that the KDR is due to heating and turbulence of the ISM by outflows and radiation from the AGN. The extent R$_{KDR}$ reaches up to 24 kpc, with a mean ratio to that of the ENLR of 57 per cent. We estimate ionized gas mass flow rates ($\dot{M}_{\rm out}$) and kinetic powers ($\dot{E}_{\rm out}$) both from the AGN broad components and from the W$_{80}$ values, that can be obtained for the whole AGN sample. We find values for $\dot{M}_{\rm out}$ and $\dot{E}_{\rm out}$ that correlate with the AGN luminosity $L_{\mathrm{ bol}}$, populating the low-luminosity end of these known correlations. The mean coupling efficiency between $\dot{E}_{\rm out}$ and AGN luminosity is $\approx$0.02 per cent from the W$_{80}$ values and lower from the broad component. But the large extent of the KDR shows that even low-luminosity AGN can impact the host galaxy along several kpc in a “maintenance mode” feedback.

Effect of growth conditions and reactor configuration on the growth uniformity of large-scale graphene by chemical vapor deposition

Chemical vapor deposition (CVD) is an affordable method for the preparation of large-scale and high-quality graphene. With the increase in CVD reactor size, gas mass transfer, flow state, and gas phase dynamics become more complicated. In this study, computational fluid dynamics is used to investigate factors affecting the uniformity of large-scale graphene growth under different growth conditions and reactor configurations. The dimensionless number defined in this paper and the Grashof number are utilized to distinguish the species transfer patterns and the flow states, respectively. A gas-surface dynamics model is established to simulate the graphene growth. Results reveal that the graphene growth rate uniformity is the highest at very low pressure and flow rate due to the flow symmetry and diffusion-dominated species transfer. At an increased pressure of 20 Torr, the uniformity of the graphene growth rate becomes higher axially and lower circumferentially with an increasing inlet mass flow rate. When the flow rate is fixed at 1500 SCCM and pressure is reduced from 20 to 2 Torr, graphene growth uniformity first increases and then decreases due to the influence of gas phase dynamics. Graphene growth rates are analyzed across ordinary reactor configurations and four configurations with inner tubes at 20 Torr pressure and 1500 SCCM flow rate. Comprehensive evaluation suggests that the ordinary reactor configuration performs best under these conditions. This research offers insights into the macroscopic growth mechanism of large-scale graphene and provides guidance for designing growth conditions in large-area graphene production.