Rod Heater Research Articles

Design and Development of 3D Printer Filament Maker Machine

Filament extruder produces plastic filaments with specified diameter by using compounding dies. Input materials (thermoplastics) are used in the form of granules and pellets and waste plastic materials can be used. Rod heaters are used to melt the input materials and Screw in used to feed the input raw materials longitudinally along the barrel. Screw is consisted of three zones namely feed, melt, and transition zone. Input raw material is melted by using rod heater Two temperature zone with six rod heaters are used to acquire maximum efficiency. Analog temperature controller is used to control the temperature of the two heaters zone. This article describes a filament extruder, which is a plastic extruder capable of making commercial quality 3D printing filament. Specifically, this paper describes the design, fabrication and operation of a filament extruder. A 2.5 mm die was used to extrude the filament at the diameter of 1.75mm. Diameter of the filament can be further reduced by using DC-motor to draw the filament coming out of the die Production can be further increased by increasing the barrel diameter above 45mm and screw diameter above 16 mm. Mechanical and thermal properties were improved by adding different fillers to the input raw material

Comparative Analysis of Different Three Types of Room Heater for Thermal Effect

he present work experimentally carried the study of comparative analysis of different type of room heater for space heating and thermal comfort. In cold climate the human being is required thermal comfort. In rural areas, humans are using the domestic heater, blower and other different types of heater for thermal comfort. Although sometimes used of these types of heater results oxygen level is down and so it is harmful to health. A comparative analysis was done in this work to reduce these problems. In these experiments, three different types of heater were used, and in the present work suggested the best type of heater for room heating in cold climate. A room is heated with a volume of 3 x 2.4 x 3.65 m3 for thermal comfort, the temperature and humidity is measured and calculates the total temperature rise and humidity drop of the room. The comfort and combine study of performance of blower, rod heater and circular heater was done in the Ramanujan hostel room at Kamla Nehru Institute of Technology, Sultanpur during night. The study was confined to 9 PM to 4 AM from January 2019 to March 2019. The experimental study was done in night so solar radiation by sun is negligible and the reading is effectively observed. Therefore, the three cases were carried experimentally for room heating in cold climate and a comparative analysis is done of these three cases (blower, circular heater and rod heater).

Simulations for L-STAR experimental gas-cooled system / CFD-Nachrechnung von L-STAR-Versuchen zur Wärmeübertragung von turbulenten Gasströmungen

Abstract Turbulent heat transfer through gas-cooled systems is a key factor for the improvements of the gas-cooled fast reactors. Within the FP7 European projects GoFastR (European Gas Cooled Fast Reactor) [1] and THINS (Thermal-hydraulics of Innovative Nuclear Systems) [2], numerical tools for the simulation of the thermal-hydraulics of next generation reactor systems were developed, applied and validated for innovative coolants. One of their objects was the L-STAR (Luft - STab, Abstandshalter, Rauheiten) facility, which has been designed and erected at the Karlsruhe Institute of Technology to study turbulent flow behaviour and its heat transfer enhancement characteristics in gas-cooled annular channels under a wide range of conditions. The test section consists of a hexagonal cross-section channel with an inner electrical rod heater placed coaxially. This design represents the flow domain around a single fuel rod in a future GFR. In this paper experimental results of the fluid flow with uniform heat release conditions for the smooth heater rod are considered. Design of the facility allows using various values of heating power and fluid mass flow rates depending on the chosen scenario. The purpose of this study is to create CFD models for the L-STAR facility, which are capable of reproducing the results of reference measurements. The other aim is to find an applicable turbulence model for the GFR relevant cases. Steady-state simulations are performed for selected cases. We also present mesh, structural element and turbulence model sensitivity studies during this work. With these model results it becomes possible to validate our CFD models to be applicable for the ALLEGRO gas-cooled reactor fuel assemblies.

Experimental study of the effects of thermally induced optical turbulence on underwater wireless optical communication link parameters

In this experimental research, the effects of refractive index fluctuations resulting from temperature fluctuations on some of the most important underwater communication link parameters such as the average received power, signal to noise ratio (SNR) and normalized power variance (aperture averaged scintillation) has been experimentally investigated. Moreover, by introducing a new probability density function which is fitted more appropriately to the experimental data obtained from our simulator tank, the bit error rate (BER) behavior of an underwater wireless optical communication (UWOC) link is also studied. These investigations are essential due to the optical turbulence limiting effects on the performance of UWOC systems. The experimental results indicate that reduction of the aperture averaged scintillation effects by using of optical components in the transmitter and receiver of UWOC links can enhance their performance. In general, increasing the strength of the optical turbulence (by increasing the temperature gradient induced by the rod heater) or the distance of the localized turbulence screen generated by temperature gradient from the transmitter plane, the aperture averaged scintillation decreases and consequently the SNR raises whilst the BER declines. Also, expanding the aperture diameter of the receiver optics reduces the normalized power variance which leads to decrease and increase in the BER and the SNR amounts, respectively. The results are presented as experimental simulation graphs.

How much aqueous sample can an inductively coupled plasma withstand?

An inductively coupled plasma can withstand the total introduction of 250 μL min−1 if infrared heating first pre-evaporates the aerosol.

Design of 3D filament extruder for Fused Deposition Modeling (FDM) additive manufacturing

Filament extruder produces plastic filaments with specified diameter by using corresponding dies. Input materials (thermoplastics) are used in the form of granules and pellets and waste plastic materials can be used. Rod heaters are used to melt the input materials and Screw is used to feed the input raw materials longitudinally along the barrel. Screw is consisted of three zones namely feed, melt, and transition zone. Input raw material is melted by using rod heater. Two temperature zone with six rod heaters are used to acquire maximum efficiency. Analog temperature controller is used to control the temperature of the two heaters zone. This article describes a filament extruder, which is a plastic extruder capable of making commercial quality 3D printing filament. Specifically, this paper describes the design, fabrication and operation of a filament extruder. A 2.5 mm die was used to extrude the filament at the diameter of 1.75mm. Diameter of the filament can be further reduced by using DC-motor to draw the filament coming out of the die. Production can be further increased by increasing the barrel diameter above 45mm and screw diameter above 16 mm. Mechanical and thermal properties were improved by adding different fillers to the input raw material

Experimental investigation on the smoldering limit of scraps of paper initiated by a cylindrical rod heater

The ignition temperature for smoldering in scraps of paper has been determined experimentally for several bulk densities under different external air flows. Beds of compressed scraps of paper were packed into a vertical combustion chamber to achieve different bulk densities and the temperature of an electrically set rod-heater was heated to temperatures between 350 and 450 °C. Once the rod-heater had reached the set temperature, the electric current supply was then turned off and the heater was embedded into the middle of the vertical combustion chamber filled with a packed bed of paper scraps. We obtained the ignition limit of the scraps of paper for different bulk densities under different external air flows by recording the temperature evolution at different positions in the combustion chamber. Results show that without external air flow, the ignition temperature first decreased with an increase in bulk density, then after a critical value, an increase in bulk density led to an increase in the ignition temperature. Furthermore, we found that even under a quiescent case (without external air flow), for the cases where ignition occurred, the smoldering front first reached the bottom side of the combustion chamber, then propagated to the upper side. As for cases with external air flows, again the propagations of the smoldering front towards the bottom side of the combustion chamber were observed in the cases where ignition happened, and external air flows played different roles in ignition limit of paper scraps bed with low bulk density, medium bulk density and high bulk density regime, respectively.

A genetic algorithm-based optimization model for pool boiling heat transfer on horizontal rod heaters at isolated bubble regime

A new optimized model which can predict the heat transfer in the nucleate boiling at isolated bubble regime is proposed for pool boiling on a horizontal rod heater. This model is developed based on the results of direct observations of the physical boiling phenomena. Boiling heat flux, wall temperature, bubble departing diameter, bubble generation frequency and bubble nucleation site density have been experimentally measured. Water and ethanol have been used as two different boiling fluids. Heating surface was made by several metals and various degrees of roughness. The mentioned model considers various mechanisms such as latent heat transfer due to micro-layer evaporation, transient conduction due to thermal boundary layer reformation, natural convection, heat transfer due to the sliding bubbles and bubble super-heating. The fractional contributions of individual mentioned heat transfer mechanisms have been calculated by genetic algorithm. The results show that at wall temperature difference more that about 3 K, bubble sliding transient conduction, non-sliding transient conduction, micro-layer evaporation, natural convection, radial forced convection and bubble super-heating have higher to lower fractional contributions respectively. The performance of the new optimized model has been verified by comparison of the existing experimental data.

A Study on Liquid Droplet and Dryout Behavior on Simulated Fuel Rod Heater under High Pressure Conditions

A Study on Liquid Droplet and Dryout Behavior on Simulated Fuel Rod Heater under High Pressure Conditions

An experimental study on critical heat flux in vertical annulus under low flow and low pressure conditions

An experimental study was carried out to investigate the phenomenon of critical heat flux (CHF) at low flow and low pressure conditions in an internally heated vertical annulus. The rod heater of the test section was made of solid stainless steel with diameter of 6mm and heated length of 454mm. The unheated outer glass tube had an inner diameter of 16.3mm. The pressure of the water coolant ranged between 116 and 228kPa, the mass flux was varied in the range of 49.88–108.53kg/(m2s) and the inlet subcooling was kept at 3°C below the saturation temperature. Among the 111 measured CHF data points 107 was detected at the uppermost thermocouple position, but four CHF were detected at lower thermocouple positions. Despite the uniform heating, the measurements showed that the CHF-location may shift from the uppermost position at L/Dhe=11.86 (heated length/heated equivalent diameter) ratio if the mass flux is lower than 63.22kg/(m2s). Five selected correlations for the low flow and low pressure range were compared with our CHF data points.

Experimental investigation on partial pool boiling heat transfer in pure liquids

Saturated partial pool boiling heat transfer has been experimentally investigated on a horizontal rod heater. The boiling liquids are including water and ethanol. The heating section is made by various materials including SS316, copper, aluminum and brass. Experiments have been performed at several degrees of surface roughness ranging between 30 and 360 micrometer average vertical deviation. The measurements are including boiling heat transfer coefficient, bubble departing diameter and frequency and also nucleation site density. The data have been compared to major existing correlations. It is shown that experimental data do not match with major correlations at the entire range of experiments with acceptable accuracy. In this article, the boiling heat transfer area has been divided in two complementary areas, the induced forced convection area and the boiling affected area. Based on two dimensionless groups, including E?tv?s and Roshko numbers, a semi-empirical model have been proposed to predict the boiling heat transfer coefficient. It is shown that the proposed model provides improved performance in prediction of the boiling heat transfer coefficient in comparison with to existing correlations.

A RBF model for predicting the pool boiling behavior of nanofluids over a horizontal rod heater

Pool boiling is an effective means of heat transfer which can handle high fluxes in boiling while maintaining minimum temperature differences over the heated surface. Addition of nanoparticles and surfactants to the base fluid are potential methods for enhancing the pool boiling heat transfer coefficient which can be useful in thermal management of complex and high performance electronic systems. This communication provides a Radial Basis Function (RBF) model to predict the behavior of a surfactant and three different types of nanoparticles on pool boiling heat transfer of water over a horizontal rod heater. In this model, the inputs include experimental condition parameters of heat flux, type of water (distilled or treated water), and concentration of SDS (Sodium Dodecyl Sulfate), nano-alumina, nano-silica with two different particle sizes, and nano-Zinc Oxide. Genetic algorithm is used for determination of the optimum values. Statistical error analysis with different parameters is also implemented for validation of the predictive model. The model is based on three sets of experiments. The effects of two different types of water, SDS and/or nano-alumina (a), the effects of two particle sizes of nano-silica (b), and the effect of combination of nano-Zinc oxide and SDS (c) on pool boiling heat transfer of water as based fluid. In all above sets of tests, the effects of the nanoparticles and SDS coated on the surface of the heater were investigated by repeating the experiments after cleaning all parts of the device except its heater surface. Furthermore, Surface Tension and Dynamic Viscosity, the two crucial thermo-physical characteristics of fluids, were determined for justifying the behavior of the materials used in the experiments. The results showed that the treated water has a better boiling performance in comparison to distilled water; the presence of SDS, Alumina, and the combination of Zinc oxide and SDS enhance the boiling performance of the base fluid; both kinds of nano-silica deteriorates the pool boiling heat coefficient of water and the smaller one has more reduction effect; the combination of the Zinc Oxide and SDS is the best coolant among the aforementioned ones. Finally, the experimental results are modeled using radial basis function neural networks and the outputs of the model are in great agreement with the experimental data.

Photographic study of bubble departure diameter in saturated pool boiling to electrolyte solutions

Bubble departure diameters during saturated pool boiling to pure water and three different electrolyte solutions including NaCl, KNO3, and KCl aqueous solutions are experimentally measured. Variable heat fluxes up to 90 kW/m2 and different salt concentrations from 10.6 to 69.6 kg/m3 are applied in order to investigate their effects on the bubble size during pool boiling around the horizontal rod heater. Visual observations demonstrated that larger vapor bubbles generate on the heat transfer surface at higher salt concentrations and lower heat fluxes in all of the solutions tested while in distilled water bubbles become slightly larger with increasing heat flux. Furthermore, the effects of different important physical properties like surface tension, viscosity, and density of the solutions on the bubble departure diameter are also discussed. NaCl solutions have surface tension higher than the other electrolyte solutions. Furthermore, the addition of NaCl to distilled water slightly increases the viscosity of the solution whereas other salts have no measurable effect on the viscosity. Therefore, it is expected that larger bubbles to be appeared on the heat transfer surface during the boiling of NaCl solutions which is in agreement with the experimental results.

Pool Boiling Heat Transfer in Diluted Water/Glycerol Binary Solutions

Pool boiling heat transfer in water/glycerol binary solutions has been experimentally investigated on a horizontal rod heater. The experiments have been performed at various concentrations (zero to 35% mass glycerol) and heat fluxes up to 92 kW m−2 at atmospheric pressure. The experimental values of boiling heat transfer coefficient have been compared to main existing correlations. It has been shown that the various predictions are significantly inconsistent. Based on the high difference between relative volatilities of water and glycerol, a simple model has been proposed to predict the boiling heat transfer coefficient. The applicability of this model is limited to low concentrations of glycerol and medium/low heat fluxes; however, the predictions are accurate. The proposed model is anticipated to be extendable to other binary systems in which the vapor pressure of one constituent is considerably higher when compared to the other component.

Experimental investigation on pool boiling heat transfer of ZnO, and CuO water-based nanofluids and effect of surfactant on heat transfer coefficient

Comparison of boiling performance of nanofluids and mixtures of nanofluids with surfactant is an objective of this research. Experimental investigation has been performed with different heat flux and concentrations of nanoparticles and surfactant. CuO and ZnO water-based nanofluids are used and sodium dodecyl sulfate (SDS) is used as surfactant. The size of nanoparticles is measured from Field Emission Scanning Electron Microscopy pictures. Roughness of rod heater is calculated by using Atomic Force Microscopy picture. The pure water is tested after each run with nanofluid and mixture of nanofluid with SDS and the results are presented. Result from experiments demonstrates that the addition of SDS to nanofluids solution resulted in improving boiling performance. Experimental results also show an inefficient process by excluding surfactant. An optimum value for heat transfer coefficient is found by increasing of surfactant concentration within CuO nanofluid (0.01wt%CuO). Pictures of coated and clean surface in boiling pure water are employed for understanding the dynamics of bubbles. Gorenflo constant (h0) is utilized to show the effect of addition of nanoparticles and SDS in boiling performance of base fluid.

Experimental investigation of natural smoldering of char granules in a packed bed

The natural smoldering of a packed bed of wood char granules was investigated experimentally. Parameters characterized experimentally included two types of ignition heaters (a rod heater and a plate heater), a range of four particle sizes (<1, 1–2, 2–3, and <3 mm), different fuel bed heights, and different ignition temperatures. The temperature inside the fuel bed and the concentration of flue gases were measured. Observations and results showed that upward smoldering is affected by many factors, and operational conditions must be rigidly controlled to achieve repeatability, while downward smoldering is stable, and smoldering time is dominated by fuel mass. This is in agreement with our earlier theoretical prediction that upward smoldering is controlled both kinetically and by mass transport, while downward smoldering is dominated only by mass transport. Experiments also showed that smoldering in the reactor is a quasi-one-dimensional process when a plate heater was utilized. Calculated results based on this case are in qualitative agreement with experiments.

G060053 FC-72を用いた垂直管内強制流動沸騰に関する研究([G06005]熱工学部門一般セッション(5):蒸発・沸騰・吸収)

RPI model is a numerical model applied to analysis of subcooled nucleate boiling heat transfer. To evaluate the accuracy of this model, experiments and numerical analyses on vertical upward boiling flow were performed in this study. The test section of experimental system has an annular channel consisted of an acrylic tube and a rod heater located in the center of the tube. The tube is 1500mm in length and 24mm in inner diameter, and the heater is 12mm in outer diameter. FC-72 under atmospheric pressure condition was used as a working fluid. In analyses, thermal-hydraulic calculations were conducted by using RPI model and a commercial code, FLUENT. By comparing analytical and experimental results, it was found the radial distributions of void fraction obtained from analyses were in good agreement with the experimental data as long as the value was smaller than 0.2. However, the rise of void fraction caused increase of the error between calculated and experimental results greatly. These results mention that RPI model cannot be applied to calculation in the condition of high void fraction.

Artificial boiling heat transfer in the free convection to carbonic acid solution

Free convection phenomenon has been experimentally investigated around a horizontal rod heater in carbonic acid solution. Because of the tendency of the solution to desorb carbon dioxide gas when temperature is increased, bubbles appear when cylinder surface is heated. The bubbles consists mainly carbon dioxide and also a negligible amount of water vapor. The results present that dissolved carbon dioxide in water significantly enhances the heat transfer coefficient in compare to pure free convection regime. This is mainly due to the microscale mixing on the heat transfer surface, which is induced by bubble formation. In this investigation, experiments are performed at different bulk temperatures between 288 and 333K and heat fluxes up to 400kWm−2 at atmospheric pressure. Bubble departure diameter, nucleation site density and heat transfer coefficient have been experimentally measured. A model has been proposed to predict the heat transfer coefficient.

Usefulness of solute elution from frozen matrix for freeze-concentration technique

A novel freeze-concentration method was proposed to use solute elution from a frozen matrix as a concentrating operation. A batch crystallizer was made up to freeze solution with a jacket cooler, and a rod heater was set at the centre of the crystallizer in order to make the solution contact with the frozen zone. Commercial apple juice was employed as a model liquid food, and the concentration behavior was investigated with the present apparatus. It was found that the concentration clearly increased with time, and the concentrate was recovered at desirable level if the temperature of the jacket and the heater were properly selected. In fact almost all the solute could be recovered from the original apple juice. The present method would mainly be governed by the solute elution from a frozen phase to a liquid phase, therefore, would not require complicated operation.

Pool Boiling Heat Transfer in Dilute Water/Triethyleneglycol Solutions

Boiling of water/triethyleneglycol (TEG) binary solution has a wide-ranging application in the gas processing engineering. Design, operation and optimization of the involved boilers require accurate prediction of boiling heat transfer coefficient between surface and solution. In this investigation, nucleate pool boiling heat transfer coefficient has been experimentally measured on a horizontal rod heater in water/TEG binary solutions in a wide range of concentrations and heat fluxes under ambient condition. The present experimental data are correlated using major existing correlations. In addition a correlation is presented for prediction of pool boiling heat transfer for the system in which the vapour pressure of one component is negligible. This model is based on the mass transfer rate equation for prediction of the concentration at the bubble vapor/liquid interface. Based on this prediction, the temperature of the interface and accordingly, the boiling heat transfer coefficient could be straightforwardly calculated from the known concentration at the interface. It is shown that this simple model has sufficient accuracy and is acceptable below the medium concentrations of TEG when the vapor equilibrium concentration of TEG is almost zero. The presented model excludes any tuning parameter and requires very few physical properties to apply.