Gas Heat Research Articles

Mode Transition Induced by Gas Heating Along the Discharge Channel in Capacitively Coupled Atmospheric Pressure Micro Plasma Jets

The effects of neutral gas heating along the direction of the gas flow inside the discharge channel of a parallel plate micro atmospheric pressure plasma jet, the COST-jet, on the spatio-temporal dynamics of energetic electrons are investigated by experiments and simulations. The plasma source is driven by a single frequency sinusoidal voltage waveform at 13.56 MHz in helium with an admixture (0.05–0.2%) of nitrogen. Optical emission spectroscopy measurements are applied to determine the spatio-temporally resolved electron impact excitation dynamics from the ground state into the He I (3s)3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}S1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_1$$\\end{document} state and the rotational temperature of nitrogen molecules at different positions along the direction of the gas flow inside the 30 mm long discharge channel. The gas temperature, which is assumed to be equal to the N2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document} rotational temperature, is found to increase along the discharge channel. This effect is attenuated as the nitrogen concentration is increased in the gas mixture, leading to an eventually constant temperature profile. The experimental data also reveal a plasma operating mode transition along the discharge channel from the Ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega$$\\end{document}- to the Penning-mode and show good agreement with the results of 1d3v kinetic simulations, which spatially resolve the inter-electrode space and use the gas temperature as an input value. The simulations demonstrate that the increase of the gas temperature leads to the observed mode transition. The results suggest the possibility of using the nitrogen admixture and the feed gas temperature as additional control parameters, (i) to tailor the plasma operating mode along the direction of the gas flow so that the production of specific radicals is optimized; and (ii) to control the final gas temperature of the effluent. The latter could be particularly interesting for biological applications, where the upper gas temperature limit is dictated by the rather low thermal damage threshold of the treated material.

Energy consumption and feasibility study of a hybrid desiccant dehumidification air conditioning system in Beirut

In this work, the transient performance of a hybrid desiccant vapor compression air conditioning system is numerically simulated for the ambient conditions of Beirut. The main feature of this hybrid system is that the regenerative heat needed by the desiccant wheel is partly supplied by the condenser dissipated heat while the rest is supplied by an auxiliary gas heater. The hybrid air conditioning system of the present study replaces a 23 kW vapor compression unit for a typical office in Beirut characterized by a high latent load. The vapor compression subsystem size in the hybrid air conditioning system is reduced to 15 kW at the peak load when the regeneration temperature was fixed at 75 °C. Also the sensible heat ratio of the combined hybrid system increased from 0.47 to 0.73. Based on hour by hour simulation studies for a wide range of recorded ambient conditions of Beirut city, this paper predicts the annual energy consumption of the hybrid system in comparison with the conventional vapor compression system for the entire cooling season. The annual running costs savings for the hybrid system is 418.39 USD for a gas cost price of 0.141 USD/kg. The pay back period of the hybrid system is less than 5 years when the initial cost of the hybrid air conditioning system priced an additional 1712.00 USD. Hence, for a 20-year life cycle, the life cycle savings of the hybrid air conditioning system are 4295.19 USD.

Optimal scheduling of electric-gas-heat system considering dual virtual energy storage of gas network management and heat network storage

Aiming at the problem of wind curtailment caused by the lack of system flexibility, an optimal scheduling strategy for improving the flexibility of the electricity-gas-heat interconnection system by the coordinated operation of the gas network management and storage characteristics and the heat storage characteristics of the heat network is proposed. Firstly, the influence of gas network storage and heat network storage on improving flexibility is analyzed respectively. Then, an electricity-gas-heat interconnected system scheduling model considering the dynamic characteristics of gas network management and t the delay characteristics of heat storage in heat network, which greatly improves the imbalance between supply and demand of flexibility in space and time brought by the anti-peak regulation characteristics of wind power to the system. Finally, the IEEE-24 nodes power system, Belgium’s 20-node natural gas network and 6-node thermal network are used, for example, analysis. The results show that the proposed scheduling scheme improves the flexibility of the system while its operating cost and wind curtailment cost are the lowest, which promotes the consumption of wind power.

Prediction of Cotton Shell from Sodecoton Behavior in Thermal Conversion and Theoretical Energy Potential

This work focuses on the evaluation of the energy potential of cotton shells from SODECOTON and to predict suitable thermal conversion conditions. To achieve this goal, structural and proximate analyses were performed, while ultimate analysis, flue gas and higher heating value were calculated from models. This study reveals that cotton shells highly contain cellulose, volatile matter, lignin and carbon, which make it suitable for bioethanol, bio-oil/syngas and biochar production via biochemical and thermochemical technologies as well as fuel briquette. Heating value from cotton shell ranging from 17 MJ/kg to 19 MJ/kg, is set in the interval to be used as fuel. From the results, the value of flue gas is within acceptable limits and the pollutant emissions are less than the values of regulated threshold set. The energy potential released is around 1.30 GJ per year, 1.58 × 107 Nm3/year, 1.62 × 104 m3/year, 15.21 × E6 L and 26 × E6 L for annual combustion energy, syngas, methane, bioethanol and bio oil, respectively. Amongst them combustion via fuel briquette is suitable for less developing country such as Cameroon thus, it could supply 40% of cooking energy consumption in Garoua center town and can improve environmental sustainability in company.

Horizontal flame spread behavior of densified wood: Effect of structural characteristics

Densified wood (DW) is a recently developed material with excellent mechanical properties, considered as an ideal construction material for high-rise timber buildings. However, its flame spread behavior has not been well understood limiting its applications. This work for the first time experimentally and analytically investigates the horizontal flame spread behavior of DW. The influences of material structural characteristics (e.g. density) on heat transfer characteristics are focused. Thermally thin DW with density ranges of 441–1025 kg/m3 and a constant thickness of 2 mm were tested. The flame spread rate, mass loss rate (MLR) and flame height decreased with the increased wood density. A power-law correlation between the dimensionless MLR and dimensionless density is proposed, which well predicts the experiments with an R2 of 0.922. The increased wood density decreases flame height and reduces flame radiation. The gas-phase heat transfer shifts from radiation-dominant to convection-dominant. The longitudinal and radial thermal conductivities of DW increased with wood density. Empirical equations are optimized to predict the thermal conductivities of DW with R2 of 0.870 (longitudinal) and 0.837 (radial). The preheating zone length and the temperature gradient per unit length don’t vary significantly with wood density. Their values are averaged to 25.62 mm and 9.312 K/mm respectively. The longitudinal heat conduction is increased with the wood density due to the increased conductivity. However, this conduction increase is lower than the radiation decrease as the wood density increases. Thus, the total heat flux is slightly decreased with the wood density. The gas phase heat transfer dominates the flame spread. However, the longitudinal heat conduction can account for more than half of the gaseous heat transfer, and thus cannot be negligible. Results of this work improve the understanding of DW flame spread, which helps to evaluate the fire behaviors of timber construction.

Gas heating by nanosecond repetitively pulsed glow discharges applied to a methane–air flame

In this work, the thermal effect induced by non-equilibrium plasma produced by nanosecond repetitively pulsed (NRP) glow discharges applied across a lean premixed methane–air flame is investigated. The flame is laminar, stationary, and axis-symmetric. The discharges are applied on the symmetry axis of the flame, crossing the fresh reactants, flame front, and burned gases. The obtained plasma-assisted flame is stable and reproducible, allowing phase-locked averaged diagnostics. The thermal effect is investigated by acquiring spatially and temporally resolved temperature measurements in the plasma discharges using optical emission spectroscopy (OES) of the second positive system of nitrogen. The results show that for an applied voltage of 10 kV, NRP glow discharges increased the gas temperature by up to 130 K within 10 ns. However, this heating was location-dependent, i.e., high near the anode tip and not detectable 0.5 mm above the anode. It was also shown that reducing the applied voltage down to 9 kV caused this ultra-fast heating to disappear. On the other hand, the reactants near the anode tip had a constant temperature of 480 K, between discharges, while the reactants were injected at 293 K. The reason for this slow heating could be due to (1) heating by the flame which is pulled down to the anode when NRP discharges are applied, (2) slow gas heating induced by relaxation of vibrational excited states of nitrogen, or (3) post-discharge oxidation chemistry. Based on temperature measurements performed on NRP corona discharges, heating by the flame could be ruled out. Zero-dimensional numerical simulations’ results suggest that post-discharge oxidation chemistry can heat the gas by 110–130 K, indicating that this is an important heating mechanism. Further investigation will be necessary to assess the significance of the vibrational–translational relaxation of nitrogen.

The carbon footprint of total knee replacements.

ObjectiveDetailed quantifications of the environmental footprint of operations that include surgery, anaesthesia, and engineering are rare. We examined all such aspects to find the greenhouse gas emissions of an operation.MethodsWe undertook a life cycle assessment of 10 patients undergoing total knee replacements, collecting data for all surgical equipment, energy requirements for cleaning, and operating room energy use. Data for anaesthesia were sourced from our prior study. We used life cycle assessment software to convert inputs of energy and material use into outputs in kg CO2e emissions, using Monte Carlo analyses with 95% confidence intervals.ResultsThe average carbon footprint was 131.7kg CO2e, (95% confidence interval: 117.7-148.5kg CO2e); surgery was foremost (104/131.7kg CO2e, 80%), with lesser contributions from anaesthesia (15.0/131.7kg CO2e, 11%), and engineering (11.9/131.7kg CO2e, 9%). The main surgical sources of greenhouse gas emissions were: energy used to disinfect and steam sterilise reusable equipment (43.4/131.7kg CO2e, 33%), single-use equipment (34.2/131.7kg CO2e, 26%), with polypropylene alone 13.7/131.7kg CO2e (11%), and the knee prosthesis 19.6kg CO2e (15%). For energy use, the main contributors were: gas heating (6.7kg CO2e) and heating, cooling, and fans (4kg CO2e).ConclusionsThe carbon footprint of a total knee replacement was equivalent to driving 914km in a standard 2022 Australian car, with surgery contributing 80%. Such data provide guidance in reducing an operation's carbon footprint through prudent equipment use, more efficient steam sterilisation with renewable electricity, and reduced single-use waste.

Numerical simulation study on microdischarge via a unified fluid model

Numerical simulation has become an indispensable tool in the study of gas discharge. However, it is typically used to reveal microscopic properties in a discharge under specific conditions. In this work, a unified fluid model for discharge simulation is introduced in detail. The model includes the continuity equation, the energy conservation equation of the species (electrons and heavy particles), and Poisson’s equation. The model takes into account some processes such as cathode electron emission (secondary electron emission and thermionic emission), reaction enthalpy change, gas heating, and cathode heat conduction. The full current-voltage characteristic (CVC) curve covers a range of discharge regimes, such as the Geiger-Müller discharge regime, Townsend discharge regime, subnormal glow discharge regime, normal glow discharge regime, abnormal glow discharge regime, and arc discharge regime. The obtained CVC curve is consistent with the results in the literature, confirming the validity of the unified fluid model. On this basis, the CVC curves are obtained in a wide pressure range of 50–3000 Torr. Simulation studies are carried out focusing on the discharge characteristics for microgap of 400 µm at pressures of 50 Torr and 500 Torr, respectively. The distributions of typical discharge parameters under different pressure conditions are analyzed by comparison. The results indicate that the electric field in the discharge gap is uniform, and that the space charge effect can be ignored in Townsend discharge regime. The cathode fall region and the quasi-neutral region both appear in glow discharge regime, and the space charge effect is significant. In particular, the electric field reversal occurs in abnormal discharge regime due to the heightened particle density gradient. The electron density reaches about 10<sup>22</sup> m<sup>–3</sup> in arc discharge regime dominated by thermionic emission and thermal ionization, with the current density increasing. The gas temperature peak is 11850 K when the pressure is 500 Torr, and the cathode surface is heated to nearly 4000 K due to heat conduction. The present model can be used to simulate gas discharge across a wide range of condition parameters, promoting and expanding fluid model applications, and assisting in a more comprehensive investigation of discharge parameter properties.

A Study on Gas Heating Using Porous Carbon as a Radiation Absorber for Solar Thermal Propulsion

A Study on Gas Heating Using Porous Carbon as a Radiation Absorber for Solar Thermal Propulsion

An applied study on energy analysis of a coke oven

In this study, the energy view of an oven of a 70-oven coke battery in an iron and steel plant was evaluated based on operating parameters and recommendations for improving efficiency were made. A mass and energy balance per coking period (p) was created for a coke oven. It was found that during each coking period, 51.2% of the energy input was used as coking heat. It is predicted that approximately 6.91% of the input energy can be recovered from flue gas into the combustion air. By recovering the heat from the flue gas into the combustion air, the efficiency of the coke oven can be increased to 58.11%. The heat of the coke oven gas can be recovered and converted into usable form, which accounts for 6.53% of the total energy input. With the dry quenching process, it is possible to recover around 24% of the energy used from coke. Improved oven insulation, heat recovery from coke and flue gases, and the dry quenching process can recover energy worth more than 25.19 GJ/p. The energy efficiency of the furnace was predicted to rise to 82.11% with coke dry quenching and to more than 88.64% with coke gas heat recovery and insulation upgrades. The potential economic savings are $2578, equivalent to a reduction in CO₂ emissions of 2.45 tons per coking period. The financial equivalent of emissions reductions from carbon trading could be $233 per coking period. Through the processes of dry coke quenching, coke gas (CG), and flue gas heat recovery and thermal insulation improvements of the coke battery, the total amount of recoverable energy can exceed 617,294 GJ/year.

Use of the heat of exhaust fluge gases of gas turbine units in recovery boilers for heat and electric supply systems

In this article, the inextricable interconnection and interdependence of the conditions for ensuring the heat of energy consumption is considered. A highly efficient installation covers the heat and energy needs of the Mubarek gas processing plant. With simultaneous operation of gas turbine and steam boiler plant efficiency reaches 95%. The introduction of the proposed development will solve the problem of energy and resource-saving, enables the use of a steam boiler in heat supply and solves an environmental problem.

New green and low-carbon technology for all-sensible heat recovery of converter gas

The smelting process of converter determines the explosive, dusty and intermittent nature of gas itself. Therefore, either the way of water (oxygen converter gas recovery system) or mist spraying (Lurgi-Thyssen system) is usually adopted to treat the converter gas after passing through the vaporization cooling flue for further reducing temperature and removing dust. This will lead to a waste of gas sensible heat resources of approximately 800–1000 °C. In this paper, an all-sensible heat recovery technology for converter gas, that is completely different from the oxygen converter gas recovery and Lurgi-Thyssen system, is proposed and implemented in an actual converter with a capacity of 100 tons. For the implementation, the new process is paralleled with the original Lurgi-Thyssen system, and successfully recovers the waste heat of converter gas through a gas-solid separator and waste heat boiler instead of an evaporative cooler. The main advantages of the all-sensible heat recovery process are reflected in the increased steam yield, the reduced energy consumption and the improved calorific value of converter gas. Obviously, this process can be used to further improve the negative energy consumption level of converter, and is expected to become the development trend of converter gas treatment in the future.

RENEWABLE HORIZONS: INVESTIGATING FEASIBILITY IN CONSUMPTION TRENDS

The European Union's ambitious target to achieve zero emissions from passenger cars by 2035 has sparked significant strategic overhauls among European car manufacturers, pushing them towards a 100% electric vehicle fleet. Concurrently, a forthcoming heating law, slated to take effect from 2024 initially in Germany, aims to drastically curtail the installation of gas and oil heating systems in favour of heat exchangers. These legislative shifts are already straining the power grid, necessitating a substantial expansion of renewable energy capacity. Projections indicate an ongoing surge in energy demand, underscoring the imperative of a global transition away from fossil fuels. However, this endeavour poses formidable challenges for nations worldwide. This study delves into the current state of renewable energy and its projected evolution, stressing the imperative of significantly boosting renewable energy deployment to achieve sustainable electrification of passenger vehicles globally. It highlights the need to triple the share of renewable energy sources, quadruple efforts across all transportation sectors, and increase the overall transition away from fossil fuels fifteenfold. While conventional renewables such as solar, wind, hydro, and biofuels remain integral, emerging technologies like nuclear fusion offer promising avenues. Nonetheless, attaining complete independence from fossil fuels may prove elusive, considering non-energy applications of crude oil and other fossil resources. The study also assesses potential ecological ramifications and balances the environmental impacts of these energy transitions.

PBF-LB of CuZn42 – Process development and material analysis

With the freedom of design and materials, laser-based powder bed fusion (PBF-LB) has become increasingly popular to improve and tailor gas flow, heat exchangers, and sensor positioning in complex assemblies. With the application of a heat-flux-burner for measuring the laminar burning velocities of hydrogen-based gases in mind, the fabrication of brass (CuZn42) by PBF-LB has been investigated in this paper. With little known research, this paper aims to do foundational work for the PBF-LB processing of this material. The feasibility was demonstrated for two different machines and empirical process models were set up to investigate the transferability of results. The relative density of cubes of different sizes and thin walls was optimized to > 99.5 % (max. 99.8 %) and demonstrated a maximum hardness of 136 HV 5. Therefore, this work demonstrated the feasibility of PBF-LB processing of brass for complex applications.

Особенности нестационарных тепломеханических процессов в выпускном коллекторе автомобильного поршневого двигателя размерности 8,2/7,1

The purpose of this work was to obtain experimental data on unsteady gas dynamics and the intensity of heat transfer of the flow in the exhaust system of an automobile piston engine for different initial conditions. The research was carried out on an experimental stand simulating the exhaust process in a piston engine in dynamics. The pressure at the outlet (in the cylinder) varied from 0.05 to 0.2 MPa, the speed of rotation of the crankshaft - from 600 to 3000 min-1. The method of thermal anemometry was used to determine the gas dynamic, flow and heat exchange characteristics of the flow in the exhaust system. Data on the instantaneous values of the velocity and local heat transfer of the flow in the exhaust system for different boundary conditions are presented in the article. The effect of the outlet pressure on the gas flow through the exhaust system and the level of heat transfer was analyzed. The spectral analysis of changes in the local flow velocity in the exhaust system is additionally presented in the article. The obtained patterns are useful in the applied aspect for clarifying engineering methods for calculating the exhaust system and for verifying mathematical models of gas exchange processes in automotive piston engines.

Improvement of the heating load calculation through analysis of the heating capacities using thermal simulation

The present study addresses the growing significance of renewable energies as a replacement for conventional gas and oil heating systems. Given the dynamic nature of these renewable energies, the integration of thermal simulations into building planning is becoming increasingly important. However, a significant portion of German standards remains static, especially the heating load calculation according to DIN EN 12831-1:2017-09. As the norm calculates the heating performance based on the day with the lowest temperatures, there is a risk that, among other things, the supply temperature will be incorrectly designed on milder days. The heating curve plays a crucial role, but it is usually adjusted only after the building's heating system is installed.

Iron particles ignition in different hot coflow temperatures

Understanding the ignition of iron particle combustion in hot environments is critical for harnessing the use of metal fuels in clean energy production. In this research work, a new single particle burner is implemented to disperse and burn iron particles using hot air coflow. The burner disperses iron particles through Coulomb forces between two air-spaced capacitor electrodes. The oxidizer coflow is heated up as it passes through a newly designed induction gas heater. Electromagnetic induction is used to heat up multiple metallic and porous heat discs by Joule heating. When the coflow gas passes through the pores of the discs, it carries the heat generated within the porous discs and delivers it to the travelling iron particles which provides ultimate heat transfer effectiveness. Coflow temperature homogeneity is examined using Schlieren imaging and confirmed by thermocouple measurements at the outlet of the coflow tube. Particle ignition and combustion occur in open space, providing excellent conditions for optical diagnostics. Two synchronized high-speed cameras were used to simultaneously determine the particle size using green laser shadowgraphy and detect iron particles ignition. Iron particles ignition experiments were conducted for a sieved patch (45–53 μm) at different hot coflow temperatures starting at 700℃ up to 900℃. The burner showed extensive capabilities to maintains a stable and homogeneous hot coflow for a wide range of temperatures up to 900℃. Ignition experiments showed 5.67 % of ejected particles are burnt at 700 ℃, while full ignition (99.33 %) can be achieved at 900 ℃.

Data Centre Refurbishment with the aim of Energy Saving and Achieving Carbon Net Zero

Queen Mary University of London (QMUL) as part of the refurbishment of one of its’s data centres will install water to water heat pumps to use the heat produced by the computing servers to provide heat for the university via a district heating system. This will reduce the use of high carbon intensity natural gas heating boilers, replacing them with electricity which has a lower carbon intensity due to the contribution from wind, solar, hydroelectric, nuclear and biomass sources of power sources. The QMUL GridPP cluster today provides 15PB of storage and over 20K jobs slots mainly devoted to the ATLAS experiment. The data centre that houses the QMUL GridPP cluster, was originally commissioned in 2004. By 2020 it was in significant need of refurbishment. The original design had a maximum power capacity of 200KW, no hot/cold aisle containment, down flow air conditioning units using refrigerant cooling and no raised floor or ceiling plenum. The main requirements of the refurbishment are: To significantly improve the energy efficiency and reduce the carbon usage of the University; Improve the availability and reliability of the power and cooling; Increase the capacity of the facility to provide for future expansion; Provide a long term home for the GridPP cluster to support the computing needs of the LHC and other new large science experiments (SKA/LSST) into the next decade. After taking into account the future requirements and likely funding allocation, floor space in the data centre and the space available to house the cooling equipment the following design was chosen: A total power capacity of 390KW with redundant feeds to each rack; 39 racks with an average of 10KW of power per rack (flexible up to 20KW); An enclosed hot aisle design with in row cooling units using water cooling; water to water heat pumps connected to the universities district heating system An overview of the project, it’s status and expected benefits in power and carbon saving are presented.

Parametric Analysis of a Radiant Gas Heating System for Controlled-Environment Agriculture with Preheated Ventilation

This article explores the fundamental principles of the software method for calculating the gas-fired heating system of a cultivation structure, where the main source of heat is provided by ceiling-mounted gas infrared radiators. To maintain the required thermal regime within the premises, a gas air heater is utilized, designed to preheat the outdoor air to the necessary temperature before supplying it to the heated space.The calculation method is based on solving a system of interconnected equations of thermal and material balances for the cultivation structure, its enclosure, and the soil surface. Possible utilization of thermal energy from high-potential combustion products of gaseous fuel is taken into account.Using the example of the “Farmer 7.5” industrial greenhouse (Russian Federation), designed for year-round cultivation of plants in closed soil (in this case, cucumbers were the subject of study until the fruitbearing stage in the winter-spring cycle), the impacts of various factors are investigated: outside air temperature, thermal resistance of the enclosing structure on the heating system’s thermal power (in combination with the gas air heater), and variable parameters of the microclimate. The latter includes the enclosure temperature of the industrial greenhouse and the intake air temperature for general exchange ventilation needs. Specific conclusions and prospects for further scientific research are drawn based on the obtained results.

Three-dimensional numerical simulation and structural optimization of large steam ejectors in exhaust gas heat recovery systems

By establishing a three-dimensional mathematical model based on the physical characteristics of the steam ejector and utilizing computational fluid dynamics (CFD) method, this study conducted three-dimensional numerical simulations to investigate the effects of five key structural parameters, namely, the length of the nozzle diffuser section, the diameter of the nozzle outlet, the length of the contraction section in the mixing chamber, the diameter of the mixing chamber inlet, and the length of the mixing chamber throat, on the ejector performance under identical operating conditions. By fitting 50 sets of simulation data using the least squares method, analytical expressions for these structural parameters in terms of the ejection coefficient μ were obtained. Subsequently, an improved firefly algorithm was employed to identify the optimal combination of structural parameters, followed by simulation verification. The results showed that compared to the single-factor sensitivity analysis method, the improved firefly algorithm obtained a superior combination of structural parameters, resulting in a 2.03% enhancement in the ejection performance of the steam ejector.