Mass Flow Research Articles

Computation of Internal Heat Source, Viscous Dissipation and Mass Flow Effects on Mono-Diffusive Thermo-Convective Stability in a Horizontal Porous Medium

Computation of Internal Heat Source, Viscous Dissipation and Mass Flow Effects on Mono-Diffusive Thermo-Convective Stability in a Horizontal Porous Medium

Thermal analysis of constant surface area tapered helical Coils: Insights from numerical modelling

Helical coils are integral to numerous engineering and domestic applications, from room heaters and vehicle suspensions to nuclear reactors, owing to their high surface area-to-volume ratio that facilitates efficient heat transfer. This study investigates the natural convection heat transfer characteristics of tapered helical coils under radiative heat loss, focusing on both straight and inverted configurations, within an unconfined air medium. The numerical simulations were validated against experimental results with a maximum deviation of 5 % before proceeding to establish the numerical findings. The analysis considers geometric parameters such as non-dimensional pitch (p*), cone angle (θ), and emissivity (ε), along with Rayleigh number (Ra), to elucidate their impact on average Nusselt number (Nu), mass flow rate of air through the coil core, and heat transfer mechanisms. Results reveal distinct behaviors for straight and inverted coils, with varying Ra and θ influencing heat transfer dynamics and airflow patterns. Notably, inverted coils exhibit enhanced heat transfer characteristics compared to straight coils. For straight coils, Nu initially decreases with increasing θ at lower Ra but rises beyond a critical θ at higher Ra due to independent heat dissipation by the coil turns. When θ changes from 0° to 50° at p* = 6, the change in average Nu is approximately 3 % and 10 % for Ra = 108 and 104 respectively. In contrast, for inverted coils, Nu increases with θ across all Ra, owing to the wider top opening facilitating airflow. Furthermore, empirical correlations are developed to predict Nu based on key parameters, achieving high accuracy with deviations of ± 6 % and ± 4 % for straight and inverted coils, respectively. These correlations provide robust tools for optimizing thermal management in diverse applications. Overall, this study contributes significant insights into tapered coil performance, essential for advancing heat transfer technology and design optimization.

Analysis of a High-Pressure Reciprocating Compressor Piston's 2D Simulation Utilizing Computational Fluid Dynamics

Reciprocating compressors represent the most renowned and extensively utilized compressors within the positive displacement category. A compressor that takes input gas at pressures above atmospheric and delivers it very high pressures (> 100 bar) is specifically called a booster pump. These pumps commonly consist of two or more piston-cylinder units in series, connected through check valves that determine the final delivery pressure, and they are instrumental in a range of applications centered around the storage and delivery of gases and fuels. Despite the availability of various booster pumps in the global market, literature offers limited insights into their design specifics. The design intricacies of a booster pump, tailored to operate at specified output pressure and mass flow rate, are contingent upon the interplay of coupled flow dynamics and heat transfer phenomena within the system. These phenomena include fluid flow dynamics through check valves, heat transfer across cylinder walls, and mechanical properties of pump materials, alongside cyclic operational parameters. To address this gap, we have embarked on an experimental-computational investigation aimed at elucidating the transport processes occurring in a single-cylinder booster pump. This work focuses on computational investigations concerning gas compression and the actuation of check valves in a single-cylinder reciprocating booster. Momentum and energy conservation equations were solved on a dynamic mesh platform through Ansys Fluent. Adiabatic conditions were employed, and the numerical solver was partially validated by comparison with thermodynamic theory for simulations conducted in a closed adiabatic cylinder. Calculations were then extended for an open cylinder with inlet and outlet check valves. Simulations indicate that forced cooling plays an important role for the longevity of sealing parts.

Application of Abrasive Water Jet Cutting on Rubber Wood Plastic Composites

Wood-plastic composites (WPCs) possess a diverse arrange of advantageous characteristics resulting from the combination of wood and plastic. These include a prolonged lifespan, cost-effectiveness, and environmental friendliness. However, the net shape can only be roughly achieved by the extrusion method used to make WPCs. WPCs require additional machining to comply with the dimensional accuracy and assembly conditions. As a result, more research into the cutting process of this composite is needed. In this work, abrasive water jet cutting was used to cut WPCs manufactured from rubber wood flour and polypropylene (PP). The emphasis was on two distinctive architectures of 1-layered and 3-layered WPCs with a thickness of 10 mm. The effects of cutting factors including water pressure, traverse speed, and abrasive mass flow rate were taken into account. The study employed a full factorial analysis to investigate the correlation between cutting parameters and cutting performance, including kerf characteristics and machined surface roughness. The abrasive and water pressure in the experiment had a significant effect in cutting both materials. In some cutting conditions, without an abrasive, non-through cutting happens, particular for the 3-layered WPC structures, that are particularly strong. An increase in water pressure decreased machining surface roughness and kerf width. The cutting parameters of 350 MPa water pressure, 30 mm/s traverse speed, and 6.67 g/s abrasive flow rate were suggested for both the 1-layered and 3-layered WPCs structures. This procedure was considered suitable for post-cutting without requiring for surface finishing.

Experimental study of abrasive water jet drilling parameters on UHMWPE for biomedical implant applications

ABSTRACT This study addresses this issue by exploring the effectiveness of abrasive water jet drilling (AWJD) as an unconventional machining approach for UHMWPE. The research employs a full factorial analysis to examine various hole characteristics, including machining time (MT), surface roughness (Ra), taper angle (TA), material removal rate (MRR), and taper ratio (TR). The study aims to understand the effect of the process features, namely abrasive water jet pressures (p), traverse rates (v), and abrasive mass flow rates (ma), on the geometry and position of the drilled holes. The results show that (v) and (p) affect the drilled hole characteristics of surface morphology, roughness, MT, MRR, TA, and TR. The microstructural characteristics of the drilled-hole surfaces are analyzed by scanning electron microscopy (SEM). It revealed that the smooth surface is attained at the lower v of 150 mm/min and ma of 250 g/min.

Near-Infrared-Based Measurement Method of Mass Flow Rate in Grain Vibration Feeding System

Near-Infrared-Based Measurement Method of Mass Flow Rate in Grain Vibration Feeding System

Discrete and continuum modelling of rock-ice avalanches: vertical segregation and its feedback on flow mobility

Rock-ice avalanches are rapid, catastrophic mass flows consisting of massive rock and ice particles in alpine regions. Varying material properties of rock and ice particles cause them to spontaneously mix and segregate during the flow. However, the impacts of segregation on the mobility remain poorly understood and are overlooked in current rock-ice avalanche models. Here, we address modeling of segregation and its mobility feedback from both discrete and continuum points of view. Using the discrete element method, we simulate rock-ice avalanches, and the segregation that occur therein, as steady gravity-driven flows of particles different in size, density, and surface friction. Segregation results in sharp particle concentration gradients which, when coupled with the large surface friction difference between rocks and ice, lead to transitions in the flow kinematic profiles. We reveal that rocks and ice contact probabilities are key to modelling the effective friction and volume fraction of the mixture flows. Continuum equations are proposed to model the concentration dependence of the pressure, while segregation-induced flow velocity profiles are modelled using the non-local granular fluidity framework that accounts for microscopic frictional interactions. The findings are expected to promote more sophisticated modeling of rock-ice avalanches necessary for hazard risk reduction and mitigation.

Retrofit of a Marine Engine to Dual-Fuel Methane–Diesel: Experimental Analysis of Performance and Exhaust Emission with Continuous and Phased Methane Injection Systems

Shipping is a highly energy-intensive sector, and fleet decarbonization initiatives can significantly reduce greenhouse gas emissions. In the short-to-medium term, internal combustion engines will continue to be used for propulsion or as electricity generators onboard ships. Natural gas is an effective solution which can be used to mitigate greenhouse gas emissions from the marine sector. Considered to be a transitional fuel, it can provide a potential reduction in CO2 emissions of around 20–30%, compared with conventional marine fuels. This work investigated the influence of diesel-injection strategies on the performance and emissions of a single-cylinder prototype compression-ignition engine for marine applications, retrofitted to run as a Low-Pressure Dual-Fuel Engine using natural gas. Two different injection systems were used: a mass flow controller enabling continuous-mode gas feeding, and a Solenoid-Operated Gas Admission Valve for marine applications, the latter allowing phased natural-gas injection. Experimental tests were focused on partial-load conditions, which are critical for dual-fuel engines, with a natural gas/diesel mass ratio of 4:1. Phased injection resulted in reductions in fuel consumption, compared to continuous mode, of up to 11%. Further experiments demonstrated reductions in fuel consumption of up to 20.7% (in equivalent diesel); on the other hand, the unburned hydrocarbon emissions which resulted were an order of magnitude larger than the reference values for full diesel, reducing the benefits in terms of greenhouse gas emissions, with a reduction in Global Warming Potential of only 3% compared to full diesel.

Numerical study of NOx emission reduction by MILD and air staged synergistic combustion in a new type of coke oven flue

In order to address the issue of high emissions in the coke industry, we require innovative solutions. This article designs a coke oven flue with an array type secondary air nozzle, achieving the synergistic occurrence of MILD combustion and air staged combustion, which can significantly reduce nitrogen oxide emissions. However, further research is needed on the optimal control methods for synergistic combustion effects. First, Analyzed the mixing state of air and fuel under different air mass flow ratios. Next, by taking into account the oxygen distribution law, analyze the temperature distribution in both the primary and secondary combustion zones. Finally, analyze the distribution of NOx concentration. Study the impact of temperature differences caused by air mass flow ratio in synergistic effects on NOx emissions. The results indicate that by adjusting the air flow ratio, the air vortex intensity in the collaborative combustion process can be enhanced. This method can reduces flame temperature, achieving the objective of reducing NOx concentration. In the new type of coke oven flue, when the air mass flow ratio is 0.4, the combustion state in the primary and secondary combustion zones is optimal, and the NOx emission concentration is 312.88 mg/m3, representing a reduction of 38 %.

Experimental Research and Improved Neural Network Optimization Based on the Ocean Thermal Energy Conversion Experimental Platform

With the progress of research on ocean thermal energy conversion, the stabI have checked and revised all. le operation of ocean thermal energy conversion experiments has become a problem that cannot be ignored. The control foundation for stable operation is the accurate prediction of operational performance. In order to achieve accurate prediction and optimization of the performance of the ocean thermal energy conversion experimental platform, this article analyzes the experimental parameters of the turbine based on the basic experimental data obtained from the 50 kW OTEC experimental platform. Through the selection and training of experimental data, a GA-BP-OTE (GBO) model that can automatically select the number of hidden layer nodes was established using seven input parameters. Bayesian optimization was used to complete the optimization of hyperparameters, greatly reducing the training time of the surrogate model. Analyzing the prediction results of the GBO model, it is concluded that the GBO model has better prediction accuracy and has a very low prediction error in the prediction of small temperature changes in ocean thermal energy, proving the progressiveness of the model proposed in this article. The dual-objective optimization problem of turbine grid-connected power and isentropic efficiency is solved. The results show that the change in isentropic efficiency of the permeable device is affected by the combined influence of the seven parameters selected in this study, with the mass flow rate of the working fluid having the greatest impact. The MAPE of the GBO model turbine grid-connected power is 0.24547%, the MAPE of the turbine isentropic efficiency is 0.04%, and the MAPE of the turbine speed is 0.33%. The Pareto-optimal solution for the turbine grid-connected power is 40.1792 kW, with an isentropic efficiency of 0.837439.

The instability marsh phenomenon and marginal stability boundary distortion of density wave oscillation in parallel channels

Density wave oscillation (DWO) in parallel channels is an important problem that has been widely studied. The marginal stability boundary (MSB) is often found to be “L" shaped on the Npch-Nsub plane, but some very different shapes were also reported. In this paper, the instability marsh region which could occur in the traditional instable region but having both instability and stability sections was presented and discussed, which is found to be an explanation of the distortion of MSB. The analysis of the instability marsh region showed that the evolution of instability marsh should be due to the stability change when operation condition changes, which can be estimated with the analysis of the two-phase and single phase pressure drop variation, as well as Ma's stability criterion for different heat flux profiles. Variation of instability marsh with different heat flux profile, inlet and outlet resistance coefficient, mass flow and pressure were obtained and analyzed, and the effects of these parameters on instability marsh variation were found to be well interpreted with stability change. The calculation and analysis of instability marsh showed a clear evolution figure of the distortion of MSB under different conditions, and related research could be helpful in better understanding the flow instability in parallel channels.

Heat transfer characteristics of vertical condensers under unsteady boundary conditions: Dynamic modeling, experiment validation, and parametric analysis

A dynamic model has been developed to predict the coupled heat transfer characteristics of vertical condensers under varying boundary conditions. The model predictions closely matched the experimental data, with normalized mean bias error and root mean square error metrics below 3%. It was observed that variations in the inlet temperature of the secondary-side coolant did not immediately affect the outlet coolant temperature, exhibiting a noticeable lag phase before gradually adjusting to new conditions. Even after the inlet coolant stabilized, the outlet coolant temperature continued to rise until reaching a steady state after a defined period. The dynamic changes in the condensate film thickness and local heat flux density were categorized into three stages: lag, transitional, and steady. These stages showed differing response and transition times across various locations of the condenser. The bottom of the condenser pipeline demonstrated the shortest response time for condensate film thickness variation but the longest transition time. Additionally, the study investigated the influence of geometric parameters on the dynamic response characteristics of condensers. It was found that longer condenser tubes, lower wall thermal diffusivity, and thicker condensing walls resulted in extended transition times for condensate mass flow at the condenser bottom.

On the impact of operating condition and testing environment on the noise sources in an industrial engine cooling fan

Engine cooling fan noise is a relevant issue for manufacturers. It is well known that both the operating point and testing environment can affect the noise generation mechanisms and, consequently, the measured noise may change. Therefore, these aspects are investigated on a reference industrial fan, for which experimental data exists, using high-fidelity numerical simulations based on the lattice-Boltzmann method. Two operating conditions, namely the free blowing and the maximum efficiency ones, and three testing environments are analyzed: (i) a conventional semi-anechoic room, (ii) an ideal free field environment, and (iii) a testing environment resembling an anechoic aeraulic facility. For cases (i) and (ii) no pressure difference across the fan is imposed, while, for case (iii), a pressure difference across the fan can be imposed. For the latter, the impact of a fully reflective and fully absorbing wall separating the two regions upstream and downstream of the fan is analyzed. At free blowing conditions, the flow over the blades is largely separated. When the blade passes through a blockage region, because of the presence of a honeycomb-like structure needed for structural purposes, it experiences a prominent loading hump. The far-field noise, at a listener located along the axis of rotation, is therefore highly tonal, with a clear peak at the blade passing frequency tone. When the same fan is tested in a free field environment, it is found that there is a difference in the acoustic pressure at higher harmonics of the blade passing frequency due to the presence of flow recirculations in the anechoic room. Placing a thin wall across the fan increases the mass flow rate, for a given rotational speed, which results in a more severe flow separation over the blades and, therefore a higher tone prominence at the blade passing frequency. If the thin wall is modeled as a sound-absorbing wall, there is a drop of the overall sound pressure level of about 2 dBA. When the fan is tested at its maximum efficiency, i.e., nonzero pressure difference across the fan, it is found that the blockage effect is less relevant. The main noise generation mechanism is the back-flow vortex induced by the pressure difference across the fan interacting with the blade tip leading edge.

Experimental study on heat storage characteristics of an air-sand moving bed heat exchanger

The air-sand moving bed heat exchanger, designed for storing fluctuating medium-temperature gas waste heat, offers significant potential for energy conservation and carbon reduction in industrial settings. However, its operational characteristics are insufficiently explored. This study investigates the heat storage process involving direct contact and cross-flow of air and quartz sand within a rectangular heat exchanger chamber. Comprehensive analyses were conducted to explore flow resistance characteristics, temperature response, and heat storage performance. Results indicate that pressure drop increases with higher air velocity and temperature, and lower air pressure, particle diameter. The relative discrepancy between fitted pressure drops and experimental data is below 10%. The primary heat transfer zone exists during particle descent. As the air-particle mass flow ratio increases, the descent rate of this zone along the airflow direction slows. Additionally, higher air temperatures elevate the optimal air-particle mass flow ratio. With inlet temperatures for air and particles set at 350 °C and 30 °C respectively, and a mass flow ratio of 0.81, an exergy efficiency of 58.93% and a power density of 600.64 kW·m−3 are achieved. These findings offer crucial insights for air-sand moving bed heat exchangers for medium-temperature gas waste heat recovery.

Optimization of liquid cooling plate considering coupling effects of heat generation and aging characteristics in power batteries

The heat generation and aging characteristics of power batteries exhibit a strong coupling relationship, and thus designing liquid cooling plates (LCPs) requires considering both aspects to achieve optimal thermal management. In this study, an electric-thermal-aging model (ETAM) correlating internal resistance, capacity, and temperature was developed. Based on this model, the effects of a serpentine LCP on the heat generation and aging characteristics of battery pack under different operating conditions were investigated using a combined simulation of zero-dimensional numerical model and three-dimensional CFD methods. Furthermore, the LCP channel widths in the length and width directions and the number of channels were optimized using orthogonal tests, artificial neural networks, and genetic algorithms, aiming to minimize battery capacity degradation. Results showed that increasing the mass flow rate of the coolant reduced the maximum temperature, temperature difference, capacity loss, and aging inconsistency of the battery pack. Conversely, reducing the coolant inlet temperature could decrease the maximum temperature and capacity loss but increased the temperature difference and aging inconsistency of the battery pack. The orthogonal test results indicated that the number of channels had the greatest impact on the heat generation and aging characteristics of the battery pack, followed by the channel width in the length direction, and the channel width in the width direction had the least impact. After optimization, the maximum temperature of the battery pack decreased by 0.57 %, the maximum temperature difference increased by 1.41 %, and the average capacity degradation decreased by 0.20 %. Moreover, with the increasing mass flow rate, the pressure drop reduction improved from 27.90 % to 33.90 %. This study may provide guidance for the design of LCPs that take battery aging into account.

Numerical investigation on thermal management performance of soft packing Li-ion batteries with oblique multi-channel cold plates

During the driving process of electric vehicles (EVs), the continuous high-rate discharge of the power battery causes significant heat accumulation. An efficient battery thermal management system (BTMS) is critical for the safe and stable operation of EVs. In this study, an oblique channel cold plate (OCCP) is designed based on the traditional straight channel cold plate (SCCP) in order to addresses the problem of excessive and uneven temperatures during the high-rate discharge of soft packing lithium-ion batteries. Effects of glycol solution concentration, coolant mass flow rate, coolant inlet temperature, oblique angle for cooling channel, ambient temperature and discharge rate for the cell on the performance characteristics of BTMS, including the cooling efficiency (φ) and pressure drop (ΔP), are analyzed numerically with Ansys Fluent software. The results show that the OCCP has better cooling performance and lower pressure loss than the SCCP. Based on the analysis with the orthogonal design method, when the glycol solution concentration is 20 %, the mass flow rate is 1.0 g/s, and the inlet temperature is 25 °C, the BTMS with SCCP could obtain the optimal performance, corresponding to that the maximum temperature (Tmax) of the battery is controlled at 32.056 °C, while the φ is 0.581, and the ΔP across the cold plate is 52.652 Pa. Furthermore, the cooling efficiency φ of the cold plate decreases with the increase in the oblique angle. When the ambient temperature is 35 °C, the OCCP with a 20° oblique angle provides the best cooling effect for the battery during a 10C discharge. This work is helpful for the design of liquid cold plates in BTMS under high-rate discharge conditions for power battery of EVs.

Numerical Analysis of Flood Invasion Path and Mass Flow Rate in Subway Stations under Heavy Rainfall Conditions

The occurrence of extreme weather, such as heavy rainfall and sudden increases in precipitation, has led to a notable rise in the frequency of flooding in subway stations. By conducting numerical simulations of flood disasters in subway stations under heavy rainfall conditions and gaining insights into the patterns of flood invasion inside the stations, it is possible to develop practical and feasible drainage designs for the stations. This paper employs the computational fluid dynamics (CFD) method, utilising the volume of fluid function (VOF) method and the renormalization k-ε group model within the vortex viscosity model. The complete process of flood invasion into subway stations with varying water levels (1500 mm, 2000 mm, and 2450 mm) is modelled, and the distribution of floods at different times under varying operational conditions is analysed to identify the evolutionary patterns of station flood history. The simulation calculations yielded the mass flow rate time history curve at the tunnel entrance and exit, which was then subjected to an analysis of its development trend over time. The total accumulated water in the subway station is calculated by integrating the difference in mass flow rate between the entrance and the tunnel exit, using the mass flow rate curve. In conclusion, the paper proposes drainage measures that provide valuable insights into pumping strategies when floodwaters infiltrate subway stations. The results indicate that the speed of flood spreading in subway stations increases with higher groundwater levels, and that the mass flow rate of floodwater entering the tunnels increases over time, eventually reaching a stable state. It was observed that, at certain times, the mass flow rate of floodwater into the tunnels exhibited a linear relationship with time.

A novel thermoelectric generator equipped with magnetized Ferro-Fluid coolant for automobile exhaust heat Recovery: A numerical study

Thermoelectric generator (TEG) is a promising energy-converting device that produces electricity from the temperature difference between a heat source and a heat sink. Enhancing the heat transfer between the TEG and the heat source or heat sink can improve the TEG performance. This study proposes a novel automobile exhaust TEG. The novelty originates from the fact that the proposed TEG uses magnetized Ferro-fluid flow as coolant to enhance cooling rate. Computational fluid dynamics (CFD) approach, through C++ coding in the OpenFOAM open-source software package, is used to assess the system’s performance. The results indicate that employing the magnetized Ferro-fluid flow can favorably reduce the cold side temperature of the TEG module, leading to a 5.5 % voltage rise. It is also shown that to achieve the same voltage enhancement without the use of the proposed magnetized Ferro-fluid flow, a tough task of a 470 % rise in the cold side mass flow rate is required. A parametric study reveals that the effectiveness of using the magnetized Ferro-fluid flow decreases with the exhaust temperature but is almost independent of the exhaust mass flow rate. This study also introduces the best location for the magnetic sources.

Novel solar-based cogeneration system: Parabolic trough integrating supercritical Brayton and organic Rankine cycles with membrane distillation

This research addresses advancements towards third-generation concentrated solar power (CSP) systems, highlighting the critical need for improved system efficiency through advanced power cycles and optimized waste heat utilisation. By integrating a direct parabolic trough solar collector (PTSC) with a supercritical CO₂ (sCO₂) Brayton cycle and direct contact membrane distillation (DCMD), coupled with a bottoming organic Rankine cycle (ORC), this study proposed a novel solution for the co-generation of power and clean water. Innovative design and optimisation methodologies for the integrated system were introduced, and a comprehensive mathematical model was developed and validated, facilitating a comparative analysis of various ORC fluids' techno-economic performance. The investigation revealed that under baseline conditions, neopentane and isobutane demonstrated slightly better cycle's net-work, whereas toluene showed significantly higher water production due to the higher mass flow rate of seawater needed, resulting from the lower condenser inlet temperature. Furthermore, parametric analysis revealed that varying ambient temperatures resulted in different optimal fluids, with cyclohexane, n-octane, n-nonane, and n-heptane achieving the highest thermal efficiency of around 36.52% at 10°C. Additionally, this study highlighted substantial exergy destruction in the DCMD desalination process, accounting for 63.12% of the exergy destruction in the bottoming cycle, predominantly at the membrane where approximately 67% occurred. Moreover, the second compression and expansion stages, especially at higher Direct Normal Irradiance (DNI) levels, contributed the most to exergetic destruction in the topping cycle. Significantly, the double cycle showed exergetic efficiency improvements between 0.12% and 0.35% across different DNI levels while in contrast, single cycles demonstrated marginally superior water production capacity. Economic analyses using bare module costing to assess the levelized cost of electricity and water, along with net present value calculations, revealed that varying ambient temperatures resulted in different optimised fluids. Notably, n-octane achieved the highest net present value, approximately 4.53% above baseline conditions, at an ambient temperature of 10°C. Finally, recommendations for organic fluids for each ambient temperature based on techno-economic optimisation were detailed.

Multi-objective design optimization and physics-based sensitivity analysis of field emission electric propulsion for CubeSat platforms

Field-emission electric propulsion is an electrostatic space electric propulsion technology that offers various advantageous features including efficient design, high specific impulse, and versatile thrust capabilities ranging from micro-Newton to milli-Newton levels. These characteristics make this type of propulsion a promising technology for small satellite platforms, enabling precise attitude control, orbit maintenance, and de-orbiting through ionization and acceleration of a liquid metal propellant. The growing demand for small propulsion systems in CubeSat platforms has spurred significant progress in modeling and characterizing field emission electric propulsion thrusters to enhance their overall performance. However, little study has been conducted to investigate the effect of geometric configurations on electric fields or expelled ion trajectories for design optimization. In this study, multi-objective design optimization is performed by incorporating electrostatic simulation coupled with an analytical performance model into evolutionary algorithms based on prediction from surrogate modeling, aiming to optimize the thruster emission design to maximize thruster performance. Physical insights into the key design factors influencing the performance of field emission electric propulsion have been gained by probing into the interaction between ion particles and electric field behavior within the thruster. It has been found that the length of the emitter tip has a significant effect on plume divergence, i.e., a longer emitter tip under the influence of electric field at higher emitter current tends to result in lower initial acceleration of emitted ions and subsequently wider spread or divergence of the ion beam. A shorter emitter tip, on the other hand, generates a sharper E-field gradient, resulting in a more focused and narrower ion beam. Additionally, sensitivity analysis has identified the mass flow rate and potential distributions as the most influential design factors on performance due to the active roles they play in the performance generation process.