Liquid Distribution Research Articles

A numerical study of liquid water distribution and transport in PEM fuel cell using Cathode-Anode model

A numerical study of liquid water distribution and transport in PEM fuel cell using Cathode-Anode model

Multiphase distribution in partly saturated hierarchical nonwoven fibre networks under applied load using X-ray computed tomography

In many industrial applications, nonwoven fibre networks are facilitated to operate under partly saturated conditions, allowing for filtration, liquid absorption and liquid transport. Resolving the governing liquid distribution in loaded polyamide-6 (PA6) fibre networks using X-ray computed micro-tomography is a challenge due to the similar X-ray attenuation coefficients of water and PA6 and limitations in using background subtraction techniques if the network is deformed, which will be the case if subjected to compression. In this work, we developed a method using a potassium iodide solution in water to enhance the liquid’s attenuation coefficient without modifying the water’s rheological properties. Therefore, we studied the evolving liquid distribution in loaded and partly saturated PA6 fibre networks on the microscale. Increasing the external load applied to the network, we observed an exponential decrease in air content while the liquid content was constant, increasing the overall saturation with increasing network strain. Furthermore, the microstructural properties created by the punch-needle process in the manufacturing of the network significantly influenced the out-of-plane liquid distribution. The method has been proven helpful in understanding the results of adaptions in both the fibre network design and manufacturing process, allowing for investigating the resulting liquid distribution on a microscale.

Numerical investigation of heat and mass transfer characteristics of steam condensation containing non-condensable gas in vertical corrugated tube

A numerical simulation of steam condensation containing non-condensable gas is conducted in this paper to analyze the heat and mass transfer characteristics in vertical corrugated tube. The species transport model, Euler liquid film model and diffusion-balance model with Dehbi factor to correct the diffusion effect are applied to simulate the mass and energy transfer processes. The effects of different corrugated tube structural parameters and inlet steam parameters on steam condensation rate, liquid film distribution and heat transfer are simulated. The results show that vortex and accumulated non-condensable gas in the corrugated region significantly influence condensation heat transfer, which are closely related to corrugation height (H=0–5 mm) and corrugation length (L=13, 16, 19, 22, and 25 mm) of the corrugations, as well as inlet velocity (Vin = 5, 7, 9, 11, 13, and 15 m·s−1) and inlet steam content (Ws = 0.6, 0.7, 0.8, 0.9, 0.99, and 1). The total heat transfer coefficient varies linearly with inlet velocity when inlet velocity increase from 5 m·s−1 to 15 m·s−1, which increase 89.6–108.1 %; total heat transfer coefficient increases almost exponentially when inlet steam content increase from 0.6 to 1, which increase 389–460 %; and the best corrugated tubes are those with corrugation height of 0.075 times diameter of tube and corrugation length of 0.325 times diameter of tube.

Visualizing liquid distribution across hyphal networks with cellular resolution.

Filamentous fungi and fungal-like organisms contribute to a wide range of important ecosystem functions. Evidence has shown the movement of liquid across mycelial networks in unsaturated environments, such as soil. However, tools to investigate liquid movement along hyphae at the level of the single cell are still lacking. Microfluidic devices permit the study of fungal and fungal-like organisms with cellular resolution as they can confine hyphae to a single optical plane, which is compatible with microscopy imaging over longer timescales and allows for precise control of the microchannel environment. The aim of this study was to develop a method that enables the visualization and quantification of liquid movement on hyphae of fungal and fungal-like microorganisms. For this, the fungal-fungal interaction microfluidic device was modified to allow for the maintenance of unsaturated microchannel conditions. Fluorescein-containing growth medium solidified with agar was used to track liquid transported by hyphae via fluorescence microscopy. Our key findings highlight the suitability of this novel methodology for the visualization of liquid movement by hyphae over varying time scales and the ability to quantify the movement of liquid along hyphae. Furthermore, we showed that at the cellular level, extracellular movement of liquid along hyphae can be bidirectional and highly dynamic, uncovering a possible link between liquid movement and hyphal growth characteristics. We envisage that this method can be applied to facilitate future research probing the parameters contributing to hyphal liquid movement and is an essential step for studying the phenomenon of fungal highways.

Experimental study of dielectric liquid spray cooling on multi-scale structured surfaces inspired by leaf veins

Dielectric liquid spray cooling is a promising way to dissipate heat of high-power electronic devices. Surface modification is a most cost-effective method to enhance spray cooling. Inspired by leaf veins, this paper designs and fabricates macro-scale, micro- and nano- scale, and multi-scale structured surfaces for dielectric liquid spray cooling. The cooling characteristics are tested on a two-phase spray cooling system using HFE-7100. The results reveal that the heat transfer is enhanced on all the structured surfaces. Two bionic leaf vein structures, reticulated veins and parallel veins, are designed for macro-scale structured surfaces. The results show that the former one is superior to the other thanks to its better liquid distribution. For the micro- and nano- scale structured surfaces, due to the larger surface area and higher thermal conductivity, the graphene coating outperforms the carbon nanotube coating in heat transfer. Multi-scale structured surfaces, featured with leaf veins and micro- and nano- coatings, further enhance heat transfer. The heat flux increases by 116 % compared with that of the smooth surface. The evaporation efficiency reaches 60 % at the surface temperature of 80 °C. Furthermore, the effect of surface temperature on the enhancement ratio of heat transfer is analyzed, revealing various enhancement mechanisms of different scaled structured surfaces.

Tuning the morphology and textural properties of ZSM-5 additive for co-cracking of waste plastics with vacuum gas oil to light olefins

Typical cracking catalysts, called equilibrium catalyst (E-Cat) are ultra-stable Y (USY) zeolite often used with 15% commercial ZSM-5 zeolite additive (ZSM-5(COM)) to boost olefin yield. In this study, similar additive zeolites with different pore sizes and acidic character were synthesized by rapid ageing of precursor solution and used in the co-cracking of low-density polyethylene (LDPE) and heavy vacuum gas oil (HVGO). Three ZSM-5 zeolites additives with Si/Al ratio 25 (ZSM-5(25)), 50 (ZSM-5(50)) and 75 (ZSM-5(75)) were synthesized and combined with E-Cat to form E-Cat/ZSM-5(25), E-Cat/ZSM-5(50) and E-Cat/ZSM-5(75) respectively. The E-Cat/ZSM-5(50) has slightly better endothermic conversion (cracking) of a mixture of dissolved LDPE and HVGO into H2, C1 to C4 gases and C2-C4 light olefins (total conversion of E-Cat 80.0%, E-Cat/ZSM-5(COM) 75.0% and E-Cat/ZSM-5(50) 83.7% respectively), with different gas, liquid and coke distributions. The E-Cat/ZSM-5(75) has 81% conversion, and highest yield of light olefins (38.4%). Structural (surface area, pore size) and chemical (acid sites) characteristics of the synthetized ZSM-5(75) zeolite explain the observed higher light olefin selectivity by different and competing catalytic routes. The ZSM-5(75) has demonstrated to be a good zeolite additive for converting dissolved plastic in HVGO into light olefins.

Performance prediction of tube-in-shell thermal storage devices with different inner tube positions using the HHO-BP neural network

This paper presents a numerical simulation study and a machine learning based prediction of the melting process in the Tube-in-shell thermal storage device. The two-dimensional Tube-in-shell thermal storage devices models are built to represent the position of the inner tube by two parameters, the eccentricity distance e and the eccentricity angle θ. The melting process of phase change material (PCM) under different conditions is simulated using computational fluid dynamics (CFD) to determine the effects of the inner tube position, inner tube radius and heating temperature on the variation of liquid phase fraction. Then, on this basis, a neural network of HHO-BP is constructed and trained by simulation data to predict the change of liquid phase fraction when the PCM melts under other conditions. The results show that the change of position in the vertical direction of the inner tube has a great influence on the melting. However, the change in the position of the inner tube in the horizontal direction has little effect on the melting rate, and the melting time is almost the same. In addition, the inner tube radius and the heating temperature both contribute significantly to the melting rate. The melting time of the model with an inner tube radius of 20 mm is 51.08 % faster than that of the model with an inner tube radius of 10 mm. The liquid phase fraction distributions of the models with heating temperatures of 60 °C and 70 °C are 0.697 and 0.935 when the melting of the models with heating temperature of 80 °C is completed. The prediction data of the HHO-BP neural network can respond to the simulation results more accurately, and all kinds of evaluation indexes are within the acceptable range. The machine learning model developed in this paper can reduce the simulation computation cost and shorten the optimization design cycle.

Effect of interaction between different plastics and polyvinyl chloride on the chlorine transformation behavior in volatiles during low-temperature pyrolysis

To reduce the pollution during the pyrolysis recovery of chlorine-containing plastic waste from different sources, effects of the interaction between different plastics and polyvinyl chloride (PVC) on the transformation of chlorine at low temperature were investigated by thermogravimetry-Fourier transform infrared (TG-FTIR) and fixed-bed pyrolysis experiments. Results showed that the proportions of chlorine in chars were all <0.04 %, indicating that almost all chlorine was released after pyrolysis. However, the chlorine forms in volatiles were significantly changed with mixing different plastics. HCl production was significantly inhibited due to the addition of other plastics, while the organic chlorinated compounds (OCCs) formation was promoted, which increased the distribution of chlorine in liquid products. During PVC pyrolysis, chlorine was mainly distributed in gas (93.09 %) in the form of HCl, only a small amount of aliphatic chlorides were generated and distributed in liquid (6.89 %). After the addition of polystyrene (PS), polyethylene (PE) and polyethylene terephthalate (PET), the chlorine distribution in liquid increased to 8.86 %, 11.98 % and 25.99 %, respectively. The formation of OCCs was significantly affected by the difference in thermochemical reaction characteristics of plastics. Specifically, the production of aromatic chlorides was promoted by PS, while the generation of aliphatic chlorides and aromatic chloroesters was significantly promoted by PE and PET, respectively. Therefore, the release form of chlorine could be significantly altered by the interaction between PVC and other waste plastics, which provides a reference for the regulation of chlorine-containing pollutants in the recovery and utilization of plastic waste.

Water in Polymer Electrolyte Fuel Cells (PEFCs): Friend or Foe? Linking Preferential Catalyst Growth with Liquid Water Distribution in PEFCs

With a recent emphasis on heavy-duty vehicle applications over light-duty, the performance targets for polymer electrolyte fuel cells (PEFCs) have become more demanding. For instance, achieving a net power output of 2.5 kW/g-PGM (1.07 A/cm2 current density) at 0.7 V is required after a 25,000-hour equivalent accelerated stress test (AST) [1]. In recent studies with traditional land/channel architecture, it has been demonstrated that Pt particle size growth is non-uniform and greater under flow field lands compared to channels [2]–[5]. It is hypothesized that preferential water accumulation under the lands during ASTs is responsible for such heterogeneity. However, a direct link between water accumulation/storage and particle size growth has not yet been established. In this study, we utilized high-resolution neutron radiography at NEUTRA, PSI, Switzerland to systematically map and quantify through-plane water content; synchrotron micro-XRD measured spatial Pt particle size distributions in fully functional fuel cells compatible with neutron imaging.The membrane electrode assemblies (MEAs) were aged using the U.S. Department of Energy’s (DOE) square-wave AST (0.6 V to 0.95 V vs. reversible hydrogen electrode, RHE) in both air and nitrogen environments at the cathode [5]. Correlations between through-plane water distribution and Pt particle size distribution maps were established for both pristine and aged samples. Understanding the role of architecture is crucial for assessing degradation, particularly in conventional flow fields where channel-land bias influences thermal and mass transport, impacting liquid water distribution. This knowledge can inform the design and engineering of PEFC components to enhance durability and reduce overall costs for vehicle applications.

Two-Dimensional Modeling of Proton Exchange Membrane Water Electrolyzer

Proton exchange membrane water electrolyzers (PEMWEs) are a central focus in the quest for clean fuel production from water. A comprehensive computational modeling of PEMWE is essential for predicting and optimizing the performance of PEMWE, enabling efficient design and advancement in clean energy technologies. In this study, a 2-D, transient, multiphysics, and multiphase model is developed to study the performance of PEMWE with a focus on morphological and geometrical features of porous transport layer (PTL), liquid saturation, gas pressure, and operating temperature. User Defined Function (UDF), an add-on of Ansys Fluent® is used to solve the transport equations in different layers of the PEMWE model. The model is first validated against experimental data (figure 1) from the literature. Mass transfer of each species (hydrogen, oxygen, vapor, and dissolved water) and heat transfer are analyzed in each layer of PEMWE, including PTL, anode catalyst layer, membrane, cathode catalyst layer, and gas diffusion layer. Besides, the electronic and ionic potential in all domains, along with the liquid water saturation distribution in porous layers, are investigated. Different governing parameters such as cell voltage, and operating temperature are varied to get the performance of the electrolyzer cell. The findings will provide new insights into electrolyzer cell performance under various operating conditions, offering valuable information for adjusting parameters and optimizing the design of electrolyzer cells. Figure 1

Numerical Study of Liquid Water Formation and Transport in Porous Media

Fundamental understanding of liquid water formation and transport in fuel cells is of great importance for achieving high durability, reliability, and maximizing cell performance. For low temperature fuel cells, water may exist as vapor or liquid phase and is involved in various electrochemical reactions and transport mechanisms. The condensation process occurs when local water vapor pressure exceeds the saturation pressure. In this work, we first investigate the permeation of liquid water in the gas diffusion layer (GDL). To this aim, a two-dimensional isothermal model considering reconstructed GDL microstructure in conjunction with VOF model is implemented. The effects of mixed wettability of materials, operating temperature, and Polytetrafluoroethylene (PTFE) loadings on liquid water transport in the porous media are investigated numerically. The liquid water breakthrough and the capillary fingering regime are captured and compared. The results show that liquid water saturation in the GDL increases with decreasing PTFE loadings. Moreover, the results demonstrated that the local microstructure in the GDL has a strong effect and can dominate the overall water distribution. To further study water condensation, the isothermal model is expanded to non-isothermal for including physics of phase change heat transfer and species transport. In addition, anisotropic thermal conductivity is incorporated to study its effect on temperature distribution and liquid water distribution. The results show that initially the liquid water is formed as micro droplets and then these micro droplets are combined to form large droplets. Moreover, the impacts of water generation rate, temperature gradient, operating pressure, and contact angle on condensation have been investigated. The findings of this work are expected to provide insights into designing more reliable GDL in fuel cells. Figure 1

Experimental characterization of dynamics of bed‐scale liquid spreading in a trickle bed

AbstractWe report measurements performed to understand the effects of gas (QG) and liquid (QL) flow rates, surface tension (σGL), liquid viscosity (μL), and particle diameter (dp) on dynamics of local liquid spreading, pressure drop, and overall liquid holdup in a pseudo‐2D trickle bed. We show that an increase in the gas‐phase inertia leads to a decrease in the lateral liquid spreading, whereas an increase in the liquid‐phase inertia leads to an increase in the lateral liquid spreading. We also show that an increase in dp causes a reduction in the lateral liquid spreading. Using dimensionless numbers (AB and We), we propose a regime map showing contributions of different forces to the local liquid spreading. We show that the interplay between the inertia and capillary forces governs the liquid distribution near the inlet, whereas the relative contribution of gravitational force increases toward the outlet. Finally, we propose a relation between AB and We for “bed‐scale” liquid spreading.

Thermal management of a battery pack using fin-embedded phase change material

Abstract The present study focuses on the numerical investigation of heat transfer from a battery cell surrounded by phase change material (PCM) with longitudinal fins embedded in it. Three-dimensional transient heat conduction equation is solved numerically in the battery domain, whereas the solidification-melting model adopting Enthalpy-Porosity approach is solved in PCM to obtain liquid fraction and temperature distribution. PCM with 16 fins was found to be quite effective in reducing the battery surface temperature compared to 12, 8, and 4 fins. However, the effectiveness of 16 fins is observed up to 1500 sec till the PCM completely melts into liquid. A maximum reduction of 25 K has been achieved at 1500 sec by adding 16 fins to PCM. Beyond 1500 sec, the temperature rises sharply, exceeding all other cases at 2200 sec. Fins play an essential role in augmenting heat transfer, which benefits in achieving the phase change process in less time to restrict the temperature rise; however, at the same time, when the phase change process completes, fins become detrimental to the system since the temperature of the battery starts rising sharply.

РОЗРОБКА І ДОСЛІДЖЕННЯ БАГАТОПОЗИЦІЙНОГО ГІДРОАПАРАТУ ТЕХНОЛОГІЧНОЇ МАШИНИ

According to the analysis of the designs of technological machines that have several executive mechanisms that work sequentially according to the technological diagrams and receive movements from the electric drive through chains of mechanical transmission mechanisms consisting of a set of kinematically connected friction pairs and parts, complicated in the design and its production, have reduced reliability in operation. The authors propose a developed hydraulic system for distributing motion to the working mechanisms of the technological machine, which consists of an original design of a multi-position, multi-line hydraulic apparatus, which can ensure the distribution of motion to several hydro motors of the working mechanisms of the technological machine in accordance with the cyclogram of its operation and replace the chains of mechanical transmission mechanisms and parts. The originality of the design of the multi-position, multi-line, single-spool hydraulic device is that it combines the properties of a spool- and valve-type hydraulic distributor, and the spool itself has a complex sectional cylindrical shape with cut sectors and makes a rotary, not reverse translational movement. The developed hydraulic device can perform both distribution and control functions and can replace controlled automatic devices. A math model for calculating the volume of the working cavities of the hydraulic device (hydraulic distributor) was developed. In order to check the operability of the hydraulic apparatus of the new design, its parametric modeling in the SolidWorks system and a cycle of experimental studies using the FloWorks module were carried out. The results of the distribution of liquid in the hydraulic apparatus for individual cavities connected to the hydraulic lines of the hydraulic motors of the working mechanisms of the technological machine were obtained. The principle of designing a new hydraulic device can be used to distribute liquid in technological machines with different cycles of mechanism interaction.

Experimental study on optimizing liquid distribution in spiral wound heat exchangers: Influence of two-phase flow parameters and geometry

The uneven liquid distribution in the shell side of a spiral wound heat exchangers (SWHEs) significantly deteriorates heat transfer in liquefied natural gas (LNG) processes. In this study, an air and water mixture was employed as a substitute for the working fluid to simulate the two-phase flow conditions in practical LNG SWHEs. The experimental investigation focused on the impact of key factors, including gas fraction, flow rate, tube pitch, and layer pitch, on liquid distribution. The findings reveal that the liquid non-uniformity index initially decreases with an increase in gas fraction, reaching an optimal gas fraction of 0.4 for achieving better liquid distribution; the liquid distribution deteriorates at high flow rates under two-phase flow conditions; the liquid distribution improves with a sparser tube pitch under two-phase flow conditions; the liquid distribution deteriorates with a sparser tube pitch at low flow rate under two-phase flow conditions, while the difference diminishes at high flow rate. Recommendations include extending the intermediate vapor quality zone and maintaining lower flow rates for enhanced uniformity in liquid distribution across the shell side. Moreover, appropriately increasing the tube pitch or reducing the layer pitch can further optimize the uniformity of liquid distribution.

Cesium stability on the interlayers of K- or Rb-fixing micaceous minerals investigated by both experimental and numerical simulation methods

The frayed edge site (FES) of micas, a partially weathered interlayer site, selectively adsorbs Cs radioisotopes. Despite extensive research on Cs+ adsorption, the interactive dynamics of FES elements remain unclear. This study employs experimental and computational methods to examine how interlayer cations at the FES affect Cs stability. We measured the solid–liquid distribution coefficients of Cs+ for partially expanded K- and Rb-fixed biotite using chemical extraction and adsorption methods. We evaluated the standard Gibbs free energy for the Cs exchange reaction between the FESs of K- and Rb-fixed muscovite models and bulk water, expanding the d001 spacing from collapsed to fully expanded conditions. Our results reveal that the interlayer cation significantly influences Cs+ affinity for FES, with the substitution of K+ with Rb+ largely reducing Cs+ stability. The computational approach further disclosed that the K+ to Rb+ replacement only at the wedge-shaped part of the FES contributed to the decrease in Cs+ stability whereas the replacement at other interlayer sites caused little impact. Our studies offer microscopic structural insights into FES, highlighting the critical role of the wedge-shaped part of FES in Cs+ stability.

Study on the uniform flow in adsorption device with perforated plate distributor

The adsorption device is widely used in the purification of impurity-containing wastewater, which is of great significance. However, the problem of non-uniform distribution of liquid in the packed bed has a large impact on the adsorption process. In the current study, CFD is used to simulate the fluid flow state during the adsorption process based on the physical modelling of the adsorption device, where the packed bed is modelled as a porous medium. By studying the effect of hole distribution, perforation rate, thickness and installation position of the perforated plate on flow uniformity and bed pressure drop, the influencing factors affecting the uniform distribution of fluid and pressure drop are discussed. Results show that changing the hole array did not have a significant effect on the fluid uniformity. When the perforation rate of the distributor is 15–29.4 %, the pressure drop is smaller and the flow distribution uniformity is better. The non-uniformity of flow field decreases first and then increases continuously with the increasing of the thickness. When the thickness of the perforated plate is between 10 and 30 mm, the overall performance is the best. Increasing the distance between the perforated plate and the inlet can reduce the impact strength of high-speed fluid on the perforated plate and improve the flow uniformity and increasing the inlet flow rate of the fluid can improve the uniformity of the flow field within a certain range, but it will increase the fluid flow loss.

Investigation On A Novel Injector Concept For Spinning Combustion Technology In High-Pressure Conditions By Advanced Laser-Based Diagnostics

Safran Helicopter Engines has recently patented the spinning combustion technology in which the burnt gases from one injector travel tangentially along the combustor annulus towards the neighboring injectors. Compared to conventional designs, the new kerosene injection systems are dedicated to improve air/fuel mixture ignition but also to further reduce NOx and soot particle emissions. Experimental studies are performed on these fuel injectors in a high-pressure/high-temperature combustion facility designed by the CORIA research laboratory. This test bench is able to reproduce the same operating conditions encountered in a helicopter combustor over the entire range of nominal operating conditions and has large optical accesses for the implementation of laser-based diagnostics. In the current paper, we present results concerning flame structure and NO formation in the primary zone under pressure conditions of up to 14 bar, using simultaneous OH-PLIF, NO-PLIF and kerosene-PLIF laser diagnostics. These experimental studies were supplemented by high-speed PIV measurements. A good spatial correlation between the distribution of liquid and vapour kerosene and the location of the flame front was observed. Depending on the operating conditions in terms of fuel/air ratio, mass flow rates and pressure, different flame structures resulting from the modification of the interaction between fuel injection and aerodynamics are observed. Furthermore, it was found that the Zeldovich pathway mainly controls the formation of NO in the vicinity of the flame front. In addition, the effects of FAR and pressure also have a significant impact on NO production. All these results are now intended to serve as a comprehensive validation database for the development and testing of high-fidelity LES tools dedicated to the simulation of reactive flows in aero-engine combustion chambers.

Impact and migration behavior of triclosan on waste-activated sludge anaerobic digestion

Triclosan (TCS), a hydrophobic antibacterial agent, is extensive application in daily life. Despite a low biodegradability rate, its hydrophobicity results in its accumulation in waste-activated sludge (WAS) during domestic and industrial wastewater treatment. While anaerobic digestion is the foremost strategy for WAS treatment, limited research has explored the interphase migration behavior and impacts of TCS on WAS degradation during anaerobic digestion. This study revealed TCS migration between solid- and liquid-phase in WAS digestion. The solid–liquid distribution coefficients of TCS were negative for proteins and polysaccharides and positive for ammonium. High TCS levels promoted volatile-fatty-acid accumulation and reduced methane production. Enzyme activity tests and functional prediction indicated that TCS increased enzyme activity associated with acid production, in contrast to the inhibition of key methanogenic enzymes. The findings of the TCS migration behavior and its impacts on WAS anaerobic digestion provide an in-depth understanding of the evolution of enhanced TCS-removing technology.

Comparison of Maximum Heat Transfer Rate of Thin Vapor Chambers with Different Wicks under Multiple Heat Sources and Sinks

In this paper, we present a new analytical model to investigate the maximum heat transfer rate of a thin vapor chamber (TVC) with multiple heat sources and sinks. The model can specifically consider different heat flux conditions for each heat source. Both capillary limitations and allowable maximum temperature constraints were employed to determine the maximum heat transfer rate. The liquid and vapor pressure distributions within the TVC were analytically derived using the Brinkman-extended Darcy equation and the Hagen–Poiseuille equation, respectively. Additionally, the theoretical wall temperature distribution was calculated based on the 3D energy equation, considering different heat flux conditions for multiple heat sources with a weighting factor. Our results demonstrate that the heat flux conditions applied to the heat sources significantly impact the internal flow pattern of the TVC. These changes in flow patterns influence the pressure distributions of the liquid and vapor, thereby affecting the maximum heat transfer rate. Furthermore, the effects of wick parameters on the maximum heat transfer rate under various heat flux conditions were examined.