Wax Melting Research Articles

Effect of air layer on PCMs melting process inside a spherical container: A numerical investigation

Efficient latent heat storage technology is getting significant interest from the researchers, scientist, and engineers who are involved in solar heating and cooling, waste heat utilization, and building energy management applications. The latter materials are employed most frequently in this connection owing to their pronounced energy storage capacity and moderate cost. The present work involves a numerical analysis for the assessment of heat transfer through paraffin wax RT42 when it is fully converted from solid to liquid phase in a spherical container with and without air layer. The interaction of the py-porosity combination was evaluated numerically with the use of ANSYS/FLUENT 16 program. The results show that the presence of a 1 mm thick air layer increased the total melting time by 33.33%, while a 2 mm thick air layer resulted in a 66.67% increase compared to the control without an air layer. In this research, it is clear that air layers play a major role in the delay of the melting of paraffin wax.

Performance estimation of hybrid rocket by varying the flow rate at multi-location swirl injector

This study attempts to evaluate the effect of varying the oxidizer mass flow rate through the secondary mid-location swirl injector on the performance of a hybrid rocket motor (HRM). The hybrid fuel used in this study was paraffin wax along with commercially available gaseous oxygen as oxidizer. Utilizing a swirl injector is crucial as it adds a tangential velocity component alongside the axial one. Introducing a secondary mid-location swirl injector heightens this effect, leading to noticeably improved performance in HRM. An increase in the oxidizer mass flow rate through the secondary mid-location swirl injector is associated with a reduction in the regression rate. This is attributed to the blowing away of wax melt layer and flame from the solid hybrid fuel grain. Furthermore, an overall increase in the oxidizer mass flow rate corresponds to a rise in combustion efficiency, closely linked to pressure development, which, in turn, correlates with the mass flowing out of the rocket nozzle. Peak thrust was observed and also maximum fuel was burnt in case where highest gaseous oxygen (GOX) rate of 50 g/s was utilized. The multi-location swirl injector assembly maintains swirling flow towards the nozzle end, presenting an optimal scenario for enhancing HRM performance.

Simulation of melting characteristics of thermal washing of the wax layer in the pipeline based on lattice Boltzmann method

ABSTRACT The escalation of transportation costs and the obstruction of pipelines due to wax deposition significantly impact the secure and efficient production of oil fields. The thermal washing method, characterized by its simplicity and cost-effectiveness, is widely employed for dewaxing crude oil gathering pipelines. The investigation of the melting mechanism of the wax layer during thermal washing is extremely important. In this paper, the two-zone composite model of multiphase flow-porous medium in the mushy zone is introduced into the solid-liquid phase change lattice Boltzmann model based on the enthalpy method, and the problem of circumferential inhomogeneity in the melting of the wax layer and the important influence of flow and heat transfer in the mushy zone on the thermal washing are systematically investigated. The demarcation point (γ tr) between the high and low liquid fraction zones is measured to be 0.81 by microscopic experiment. The impacts of varying γ tr and Ste numbers on wax melting at different circumferential locations are analyzed in detail. The results show that the melting efficiency of wax exhibits a nonlinear enhancement from − 90° to 90°. The melting efficiency of wax decreases with increasing γ tr for wax layers between 90° and − 45°. The melting efficiency of wax increases with higher Ste numbers at all angles. The Ste number increases from 0.42 to 5.0, and the melting efficiency of the wax layer at angles ranging from 90° to − 90° increases by factors of 2.16, 2.16, 2.20, 2.61, and 3.33 respectively. The growth of the Ste number improves the warming rate and shortens the generation time of convection at the center point of the wax layer. The research findings serve as a fundamental reference for formulating a rational and efficient thermal washing scheme.

Versatile Application of Polymeric Gel Using Gelatin Polymer

Fragrance chemicals have been utilized to refresh the air and hide smells since antiquity. Electric air fresheners have a 30% market share, sprays, including aerosol air fresheners, have a 27% market share, car air fresheners have a 16% market share, gel air fresheners have a 9% market share, candle air fresheners and wax melts have a 7% market share, liquid air fresheners have a 6% market share, and others. According to research studies, 34.7% of the population in the United States experienced health concerns such as migraine headaches and respiratory difficulties after being exposed to fragranced items. As a result, there are various studies that show that fragmented items might have harmful health impacts on the general population.Given that air, fresheners have been linked to undesirable negative health impacts, the motivation for developing a greener and healthier method of synthesis of gel air fresheners. The gel air fresheners in this work were created utilizing a simple and green sol-gel reaction that included natural biodegradable polymer gelatin and mogra essence, as well as silver nanoparticles and ampicillin drug for antibacterial gel. In any case, the gel air freshener made from mogra essence is safer for human health than commercially available ones. According to the findings of this investigation, there should be future improvements in stability.Weanalyze the property of the gel from different analysis methods like SEM, TGA, FTIR, and XRD.

Melting and removing wax deposition by thermal washing in oil well

Wax precipitation has proven to be a serious problem when extracting the crude oil from current oilfields. Thermal washing is one of the common methods to remove wax deposition in oil wells. Mastering the melting process and the melting time of the wax layer in thermal washing is essential to optimize operating parameters and further improve the efficiency of thermal washing. In this paper, the scouring model and the melting model are carried out to simulate wax melting behaviour during the thermal washing process in a vertical oil well. Furthermore, with the melting model, the effects of five factors on the melting time have been studied. The results reveal that the melting time is mainly influenced by the thickness of the wax layer and the water flow rate, while the initial temperature of the wax layer, water temperature and inner wall temperature of tubing these three temperatures have a relatively slight influence on the melting time. Finally, with the numerical simulation results, a correlation is developed to predict wax melting time and verified with thermal washing time of the Cha well. It indicates that the melting model is applicable for most of the waxing section, while the scouring model is only applicable when the water initially reaches the bottom of the waxing section, so the melting model is more practical for thermal washing in the oil well.

Numerical study of heat transfer characteristics of phase change materials reinforced with porous media based on hybrid mesh

To address the drawbacks of inadequate energy density as well as utilization effectiveness in solar energy utilization, phase change energy storage offers a possible option. However, the low thermal conductivity of traditional phase change materials (PCMs) restricts the extent to which solar energy utilization can be enhanced. In this paper, the impact of the metal foam (MF) on the solid–liquid interface, the flow field, the enhancement heat transfer mechanism during the paraffin wax (PX) melting process and thermal storage characteristics was analyzed. Besides, a three-dimensional mathematical model of MF-PX using the hybrid mesh technique was established and software ANSYS-FLUENT was used for simulation. The results indicated that, the hybrid mesh exhibited a reduction of 52.75 % in mesh count compared to the unstructured mesh, resulting in 45 % reduction in computational time. Moreover, the hybrid mesh also showcased improved mesh quality that the unstructured mesh was mainly distributed in the range of 0.48–0.6, while within the range of 0.84–1.0 for the hybrid mesh. More important, the maximum relative error between experimental and simulation was 8.67 %, indicating that the model can make a reasonable prediction. With the proportions of MF increased from 0.11 % to 0.43 %, both the Rayleigh number (Ra) and its amplification decreased. At 800 s, the Ra decreased from 1.76E+07 to 1.20E+07, while the amplification of the Ra was reduced from 1.88E+07 to 1.30E+07. In addition, the natural convection proportions of CMF decreased from 96.31 % to 80.65 %. These observations indicated that natural convection was the primary heat transfer mechanism, and the conduction was enhanced by the increasing proportion of MF. Finally, in terms of heat storage characteristics, the heat storage capacity and heat storage rate of the composite PCM slightly decreased. The heat storage values decreased from 19.30 kJ to 18.66 kJ. Similarly, the heat storage rates decreased from 19.86 J/s to 18.81 J/s.

Application of Solar Energy to Liquify Beewax

This study investigates the feasibility of using solar energy for melting recycled older combs and capping wax byproducts to create raw beeswax. The solar-driven beeswax melter is composed of a stainless steel container, a lean-to structure featuring polycarbonate sheet covers, a wooden solar heater, and parallel arrays of PV solar panels. The research contrasts three distinct approaches for melting beeswax: the conventional water bath technique, exclusive reliance on solar energy for melting, and the combination of solar energy and supplementary heat from solar panels. The traditional water bath method's effectiveness and the bulk temperature of the liquified beeswax were gauged. In the case of the solar-powered wax melting setups, the process's efficiency, the melted wax's bulk temperature, and various macroclimatic factors such as sunlight radiation, temperature, and relative humidity were documented. Based on the experimental outcomes, the beeswax melting efficiency was determined to be 73.4% for the traditional water bath method, whereas it escalated to 85.5% and 87.2% for the solar approaches, respectively. Hence, the utilization of solar techniques for beeswax melting is recommended.

Simulation of Heat Transfer during Paraffin And Gallium Melting and Solidification Processes Utilizing Star CCm+

Energy storage systems are essential as the world works to minimize its dependency on fossil fuel energy for environmental and economic reasons. Because of their high capacity for latent heat storage. The numerical study of benchmark cases of solidification and melting was undertaken, and the results of these investigations are presented in this project. Numerical analysis is conducted to examine the brief solidification process of a pure liquid phase-change material within a rectangular enclosure when natural convection is present. The horizontal boundaries are both taken to be adiabatic, with one vertical barrier maintained at a temperature below the material's melting point and the other above. In this work, a numerical investigation of the melting of wax (namely N-octadecane) is presented. The numerical simulations of the experiments were carried out using STAR CCM+, and the results were compared with the results of other numerical simulations (FLOW 3D). The numerical simulations of gallium melting were carried out with a commercial code, STAR CCM+, which captures the solid-liquid interface with a fixed grid. This software captures the solid-liquid interface for phase change simulations in complex geometries with the enthalpy formulation technique. In addition, it demonstrates that computational fluid mechanics has reached a state of development where it permits reliable flow computations with solidification and melting. Casting with metal melts can be studied to provide information to engineers during the design process of new casting tools. The available simulation tools can also be used to predict existing casting processes and determine the origins of defects. The key findings are as follows: The interface shape during the solidification of gallium from above is always determined in large part by anisotropy in heat conductivity and interface growth morphology. Natural convection in the liquid slows down the rate of melting and adds more complexity to the morphology and transport mechanisms at the interface.

A novel two-dimensional continuum mixture theory model for paraffin wax melting in a cavity heating from side considering volume change

Paraffin wax presents a considerable potential for thermal storage technologies, given its high latent heat. Therefore, the accurate and systematic modeling of its melting process bears significant importance. Yet, existing mathematical models fail to adequately address the velocity driven by the density change during the melting process. In this research, we introduce a novel model for paraffin wax melting within a square enclosure subject to side heating. Unlike current models, our approach posits that flow within the mushy zone is dictated by the mass equation, not Darcy’s equation, and thus excludes the usage of mushy zone constant. This assumption, premised on the idea that the density-deviation-driven flow precludes the bulk flow from penetrating the mushy zone, is confirmed through a carefully designed visual experiment. Utilizing our melting model, we construct a mathematical model anchored in the continuum mixture theory. Through a comparative analysis of results acquired by numerical methods and experimental data, we find that our innovative mathematical model effectively predicts real-world scenarios with remarkable precision. Furthermore, we explore the influence of flows within the mushy zone on the melting process. Our findings indicate a significant deviation in results when assuming zero velocity in the mushy zone, suggesting that the density-deviation-driven flow is numerically negligible. However, it is crucial to note the physical relevance of the density-deviation-driven flow in accurately predicting the melting process. The absence of this consideration allows the bulk flow in the liquid region to permeate the mushy zone, thereby introducing substantial errors.

Formation and In Vitro Simulated Digestion Study of Gelatinized Korean Pine Seed Oil Encapsulated with Calcified Wax

Natural waxes have demonstrated exceptional potential as oil gels for saturated and trans fatty acids, but their application has been limited by issues such as temperature sensitivity, lack of stability and durability, and compatibility. In this study, three types of wax (Beeswax (BW), Rice bran wax (RBW), and Carnauba wax (CW)) were combined with calcium hydroxide to produce calcified wax. The calcified Korean pine seed oil gel obtained by heating and stirring with Korean pine seed oil is responsive to temperature and has environmental adaptability. The effects of critical gel concentration, temperature regulation, texture properties, microstructure, oil-holding capacity, and FT-IR on the quality parameters of oil gel were investigated. Additionally, an in vitro digestion model was developed to comprehend the decomposition rate of fat during gel structure digestion and transportation. The results demonstrated a close correlation between the critical gelation concentration and calcium ion content. Furthermore, after calcification, the hardness followed the order BW > CW > RBW. Moreover, there was an approximate 10 °C increase in wax melting point. Conversely, BW:Ca exhibited the lowest oil leakage. The microstructures revealed that the oil gels formed post-wax calcification exhibited similar fractal dimension (Db) values (<7 μm), and the intermolecular forces were characterized by van der Waals forces, which were consistent with those observed in the non-calcified group. In conjunction with the vitro digestion simulation, our findings demonstrated that RBW and CW oil gels gradually released 20%, 35%, and 35% of free fatty acids (FFA) within the initial 30 min of intestinal digestion. Importantly, the FFA release rate was significantly attenuated, thereby providing a foundation for developing wax-based gel processed foods that facilitate gentle energy release benefits for healthy weight management.

Tuneable Topography and Hydrophobicity Mode in Biomimetic Plant‐Based Wax Coatings

AbstractAcross diverse natural surfaces, remarkable interfacial functionalities emerge from micro and nanoscale self‐assemblies of wax components. The chemical composition of the epicuticular wax prescribes the intrinsic crystal morphology and resultant topography of the natural surfaces, dictating their interfacial wetting properties. The potential of regulating the topography of identical wax compositions through various crystallization routes is tested here. Crystallization through solvent evaporation produces diverse topographies with enhanced surface hydrophobicity compared to the slow cooling of the wax melt. Further, the microscale interfacial crystalline structure can be deliberately designed to operate in sticky or slippery hydrophobic regimes through control of the supersaturation level during the crystallization process. While the supersaturation level significantly impacts surface wettability by modulating the microscopic aggregation of rice bran wax crystals, the crystal structure at the molecular scale remains effectively unchanged. The relationships between the supersaturation level, surface topography and hydrophobicity modes, primarily derived for rice bran wax, are qualitatively validated for a wider range of plant‐based waxes. Crystallization of inherently hydrophobic plant‐based waxes from thermodynamically isotropic solutions offers an affordable single‐step approach for the fabrication of biodegradable hydrophobic coatings, applicable to versatile materials and geometries.

COOLING OF CONCENTRATED PHOTOVOLTAICS WITH PHASE CHANGE MATERIAL AND FINS

The increase in cell temperature with increased irradiance is probably the most significant disadvantage of using photovoltaic with reflector modules. In this study, a developed Phase Change Material system was integrated into the rear section of a concentrating Photovoltaic system to limit its temperature rise. The heat transmission of the concentrating photovoltaic with a phase change material system was investigated using an experimental method and a numerical method. The temperature distribution was simulated numerically using ANSYS 2021 three-dimensions model. Three cases were studied: one without wax, one with wax, and one with wax and fins. The results displayed convergence between the experimental results and the numerical results. The effect of using phase change materials on performance and efficiency of concentrated photovoltaic cells, the amount of temperature reduction through the wax melting period for concentration with paraffin wax and concentration photovoltaic with fin and paraffin wax by 2.8 °C and 6 °C, respectively, as well as an enhancement in efficiency of photovoltaic at the noon time of cases by 1.807% and 3.182% related to the reference photovoltaic. The outcomes also demonstrated that using fins aids in the distribution of temperatures, resulting in regular melting of wax in comparison to wax without fins.

Improving of Paraffin Wax Properties by Adding of Low Density Polyethylene (LDPE)

Petroleum wax is a polymer completely similar to ethylene with a high degree of crystalline and linearity. The method of mixing polymer with wax is one of the most common methods used in the field of improving the specifications of polymeric materials and making them widely used in various industrial fields. By mixing wax with different proportions of the polymer, to obtain better specifications in terms of solubility, hardness, thermal stability, and chemical resistance. Thus, it can be used in the electrical industries. This study examines some characteristics of the prepared wax such hardness, melting point, ash percentage, and electrical conductivity. The process of mixing with different percentages of wax, polyethylene and nano silver led to a clear increase in the electrical conductivity property, as the increase in the proportion of nano silver led to an increase in electrical conductivity. The polymer worked to prevent silver nanoparticles from clumping and making them cover the surface of the polymer, and thus an electrical circuit was made without metal wires.

Magnetoconvection driven melting of nanoenriched paraffin wax in cubical enclosure

The latent heat thermal energy storage using phase change material plays a vital role in thermal power production, solar energy storage and nuclear reactors. The dispersion of metallic nanoparticles into phase change material in the presence of magnetic field controls the natural convection induced melting process. This paper numerically investigates the thermo-magnetic turbulent convection induced melting of nanoenriched paraffin wax dispersed with hybrid magnetic nanoparticle pairs in a cubical enclosure with hot bottom wall. The magneto free convection effect on the melting process is investigated for high value of Hartmann number and Rayleigh number. The melting characteristics is modeled using enthalpy-porosity formulation discretized using finite difference technique and the computations are performed using an in-house three-dimensional code. It is found that the natural convection induced melting generates quadruplet thermal plume patterns from the melt zone. The dispersion of hybrid nanoparticle pairs of ferrous ferric oxide and multi-wall carbon nanotubes for particle volume fraction of 4% enhanced the melting fraction and average Nusselt number of paraffin wax by 75.21% and 42.16% respectively. The high Lorentz force developed for turbulent Hartmann number of 2000 diminished the convection induced melting phenomena. The melting time and melting rate of nanoenriched paraffin wax are a decreasing function of Hartmann number and it decreased the melt pool velocity and kinetic energy by 73.5% and 71.42%. The increase in Hartmann number decreased the average Nusselt number of nanoenhanced paraffin wax by 20.88%.

Baking using oleogels

Baking using oleogels

Investigation of the role of electrohydrodynamic forces on the heat transfer enhancement and solid extraction during melting of paraffin wax under constant temperature boundary conditions

The melting enhancement of paraffin wax is studied experimentally under the effect of electrohydrodynamic (EHD). Paraffin wax was melted under constant temperature boundary conditions with different applied DC voltage magnitudes and polarities, and different temperature gradients. The role of EHD forces was investigated by applying DC and AC square waves with different frequencies and offset values.It was found that the melting enhancement rises nonlinearly with increasing the voltage magnitudes. The maximum effective thermal conductivity under -10 kV was found to be 0.95 W/m-K in comparison with the value of 0.2 W/m-K for the pure liquid paraffin wax, with an enhancement ratio of 4.75.The EHD solid extraction phenomenon investigation showed that the extraction was detected for all the applied DC voltages. Small dendrites were observed to be pulled out from the mushy zone melt front and rise upwards in a rotational manner. It is concluded that the Coulomb force is the primary force for extraction while the formation of electroconvection cells is the main driving mechanism for the motion of the suspended dendrites in the liquid bulk. In addition, the AC studies revealed that the dielectrophoretic force is negligible in this study.

Sulfur dioxide maintains storage quality of table grape (Vitis vinifera cv ‘Kyoho’) by altering cuticular wax composition after simulated transportation

The cuticular wax layer as a natural defensive barrier plays a key role in postharvest fruit quality maintenance. This study investigated the effects of simulated transport vibration (STV) on the berry quality and cuticular wax, and the ability of sulfur dioxide (SO2) to ameliorate STV damage in table grapes during cold storage. Results showed that STV damage accelerated the deterioration in grapes quality, and resulted in degradation and melting of cuticular wax, accompanied by a decrease in load of total wax, triterpenoids, fatty acids, alcohols, and olefins while an increase in alkanes and esters content during subsequent storage. However, SO2 effectively reversed the adverse impact of STV damage by increasing most wax fraction levels and corresponding genes expression, especially triterpenoids, although it had no apparent effect on wax structure. Overall, SO2 delayed the quality deterioration caused by vibration damage that occurs during transportation and storage by altering cuticular wax composition.

Numerical Study of Paraffin Wax Melting in a Cavity with A Gradient of Hot Wall Inclination

The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A was 9.4% faster, Model-B was 3.8% faster, Model-D was 2.3% slower, and Model-E was 3.2% slower.

A comprehensive study on melting enhancement by changing tube arrangement in a multi-tube latent heat thermal energy storage system

In this study, the paraffin wax's melting dynamics in a multi-tube latent heat thermal energy storage system are investigated. The performance of ten arrangements of five heat transfer fluid tubes is compared. The radial eccentricity of four planetary tubes is varied around a fixed central tube. The study aims to find an appropriate arrangement of multiple HTF tubes keeping the same PCM content and heating surface. A simplified two-dimensional computational domain was considered, an enthalpy-porosity based melting model was designed, and the governing equations were solved using ANSYS-Fluent. The melting sequence in various cases is represented as the liquid fraction contours, flow streamlines, and temperature contours. The performance of proposed designs is assessed on the basis of transient plots of liquid fraction, average domain velocity, and heat flux at the outer surface of the heat transfer fluid tube. It is observed that the melting dynamics are greatly influenced by the tube arrangement. The coalescence of small vortices and the intermixing of different temperature layers accelerate the melting. It is found that the tubes in the top half should be placed closer to the center to delay thermal stratification, and in the bottom half should be placed deeper into the poor melting zone. The staggered arrangement of planetary tubes outperforms the inline arrangement at given eccentricities. The fastest and slowest melting is realized by Case 9 and Case 1, which take 128 and 269 min, respectively, for melting. The proposed designs can store 1450 kJ/m of energy with 98 % theoretical efficiency.

Effects of temperature and pressure on wax precipitation and melting characteristics of oil-gas condensate: an experimental and simulation study

The BZ and DB blocks in Tarim Oilfield (China) are condensate gas reservoirs operating under high pressure and high temperature. To mitigate and control the problem of wax deposition, in this study, the wax appearance temperature (WAT) at different cooling rates and wax melting temperature (WMT) at different heating rates of the condensate oil were tested using differential scanning calorimetry. In addition, the crystalline behaviors of wax during precipitation and melting were observed from a micro perspective. By considering the components of the condensate gas and the production data, the carbon number distribution of the well fluids under stratigraphic conditions was simulated. Based on the results, the phase envelope of the well fluids was also simulated, and the relationships between the phase and the temperature and pressure of the oil-gas condensate were analyzed. The temperature and pressure at different depths of the wells were simulated. It was found that the WAT decreased with increasing cooling rate and the WMT increased with increasing heating rate. Furthermore, the wax content of the oil-gas condensate in DB was higher than that in BZ. Finally, it was predicted that wax precipitation occurred above the depth of 500 m in the BZ well.