Number Of Fins Research Articles

Влияние на технически и технологични параметри на вентилатор на въздушно ротационен разпръсквач върху разпределението на работната течност при третиране на трайни насаждения

The protection of agricultural production from enemies must be carried out with maximum protection of the treated plantations and targeted utilization of the working fluid. Therefore, it is necessary that the distribution of Растениевъдни науки, 2023, 60(5) Bulgarian Journal of Crop Science, 2023, 60(5) https://doi.org/10.61308/IBBX3165 89 the working fluid is consistent with the parameters of the treated object. In this context, the influence of the technical parameters and the mode of operation of three air rotary sprayers on the distribution of the working fluid was investigated. It was established that the formed air torch from the three different spraying bodies, with different diameter and number of fins, affects differently the nature of the distribution of the working fluid in height, and the frequency of rotation very little affects the relative distribution. Research shows that the choice of one or another working body must be consistent with the formation of the treated vineyard or orchid garden. In accordance with the nature of the relative distribution, the use of fan rotary spreader a diameter of 600 mm in the predominant treatment of vineyards and 500 mm in the treatment of orchards can be recommended.

Effect of micro-fin tube geometry parameters on evaporator material savings

A Performance Evaluation Criteria (PEC) analysis is presented that explores the influence of the micro-fin tube geometry on the required material volume. The analysis was done using a local flow boiling model, which can quantify the effect of fin parameters and the tube diameter. The PEC was done while requiring that the compared surfaces satisfy the same heat duty and pressure drop. The following tube parameters and ranges were explored: tube diameter (3 mm ≤ Do ≤ 6 mm), fin base thickness (0.12 mm ≤ tbf ≤ 0.29 mm), helix angle (6° ≤ α ≤ 30°), fin apex angle (11° ≤ β ≤ 22°), total number of fins (43 ≤ nf ≤ 70), and the fin height (0.11 mm ≤ e ≤ 0.3 mm). The tube that provided the smallest material requirements within the examined parameter ranges had: Do = 3 mm, tbf = 0.12 mm, α = 6°, β = 11°, nf = 43, and e = 0.3 mm. In general, small Do and tbf and large nf and e provided the best performance and work to minimize the required material volume to provide a given heat duty and pressure drop. The helix and the fin-tip apex angles were found to have very little influence on the performance for the examined range of parameters and angles associated with the lowest production cost should be chosen.

Heat transfer enhancement in finned annulus of elliptic-circular heat exchanger

In this numerical study, a trapezoidal finned elliptic-circular heat exchanger is investigated for thermal performance based on the various geometrical parameters. The inner core of this exchanger is circular and augmented with trapezoidal fins longitudinally, whereas the outer core is elliptic. For the first time, the trapezoidal fins are used in this specific duct configuration. The configuration of the proposed heat exchanger depends on the number of fins, fin height and ratio of the radius of the inner circle to the semi-minor axis of the ellipse The material of the inner circular core and trapezoidal fins is assumed to have infinite thermal conductivity. The constant heat flux condition is imposed on the inner pipe and trapezoidal fins, whereas the adiabatic condition is considered for the outer elliptical core of the heat exchanger. The simulation is performed using the finite volume method based on the software ANSYS Fluent. The friction factor (fRe) and Nusselt number (Nu) have been computed and plotted for various fin configurations. The results suggest that the performance of the heat exchanger can be effectively influenced by the number of fins, fin height and radius of the inner circular pipe. For practical interest, a larger number of trapezoidal fins with a higher height and are recommended.

Parametric analysis of a solar parabolic trough collector integrated with hybrid-nano PCM storage tank

ApplicationNewly developed fluid called phase change materials (PCM) used to accumulate solar thermal energy. This paraffin-based fluid is mixed with hybrid nanoparticles composed of titanium dioxide “TiO2″ and copper oxide “CuO”. Using this fluid, we hope to improve the efficiency of industrial solar thermal installations. Purpose and MethodologyA computational fluid dynamics (CFD) model was developed using Ansys Fluent 19, coupled with a home code implemented in the C programming language as a “user-defined function”. Initially, the model was validated against experimental data, then a parametric study was conducted to investigate the impact of pure paraffin PCM and hybrid nanoparticles-paraffin PCM, as well as the effect of varying the mass fraction of nanoparticles and the heat transfer fluid flow rate. geometric parameters such as the number of fins installed in the storage tank were also considered during the analysis. Major findingsOn the basis of the obtained results, it was found that the incorporation of paraffin phase change materials (PCMs) within a storage tank has the potential to significantly prolong the operational duration of solar systems. Additionally, hybrid nanoparticles at 1% concentration increased the average storage tank temperature by 8% and decreased the melting time by 13.29% compared to pure PCM.

Thermal and viscous irreversibilities in the heat exchanger of individually finned heat pipes using freon R404A as the working fluid

This work aims to apply a theoretical procedure to determine the performance of the heat exchanger of individually finned heat pipes used in an air conditioning system. The relevant physical quantities are defined and specified locally in the evaporator and condenser sections. The results obtained in the sections are associated with the theoretical determination of the global performance of the heat exchanger. Global theoretical results are compared with global experimental results. Thermal effectiveness, heat transfer rate, pressure drop, thermal and viscous irreversibilities, and thermodynamic Bejan number are determined at the evaporator, condenser, and heat exchanger. The relevant variables used to determine the results are the number of fins per heat pipe and rows of heat pipes. The theoretical-experimental comparison demonstrates that the localized model applied in the analysis is consistent and can be used as a design and comprehensive analysis tool for finessed heat exchangers. The performance of the heat exchanger demonstrated exceptionalness when comparing irreversibilities through the Bejan number, indicating a favorable cost-benefit ratio for the fins less than 30 and the number of heat pipes equal to 49. Bejan’s thermodynamic number, which uses results related to thermal and viscous irreversibilities, demonstrated that one should look for the relationship between thermal irreversibility versus total irreversibility and that fin numbers between 10 and 20 for heat pipes equal to 49 provide a better cost-benefit ratio. The absolute percentage errors obtained between theoretical and experimental values, for an experimental number of fins equal to 30, for the overall heat transfer rate and overall thermal effectiveness range from 2.0% to 42.1%.

Theoretical thermal performance of cross-flow finned heat pipe heat exchanger used for air conditioning in surgery rooms

The thermal efficiency of heat exchangers was applied for theoretical analysis of the thermal performance of a finned heat pipe heat exchanger (FHPHE) used as an auxiliary device to control the temperature and quality of the air conditioning in operating rooms. The theoretical analysis performed is punctual and distributed. It is divided into three aspects: analysis of the evaporator section, analysis of the condenser section, and analysis of the heat exchanger in terms of overall performance. The distributed procedure contrasts with the theoretical-experimental study, which uses the concept of thermal effectiveness (ε-NTU) for global heat exchanger analysis. The developed approach considers the number of heat pipes, the number of fins, and the flow rate variation at the inlet of the heat exchanger as fundamental parameters for determining the thermophysical quantities of interest. Theoretical values were determined for the average velocities, Nusselt numbers, thermal effectiveness, heat transfer rates, and exit temperatures. The localized theoretical-experimental comparisons are consistent, and the absolute relative error for the global heat transfer rate ranges from 0.5% to 35%.

Badger Ballistics Midwest High Powered Rocket Launch Proceedings Report

In this competition, UW-Madison AIAA was tasked with building one team rocket and seven accompanying rockets to be launched, each with unique design aspects. To design the rockets, OpenRocket simulations were used as well as SolidWorks. The rockets differed in a multitude of ways including number of fins and parachutes, motor size, and material. The fin numbers ranged from three to six fins and the team rocket featured dual deploy parachutes versus single deployment in the other seven rockets. The rockets featured two motor brands Cesaroni and Aerotech, with H, I & J level motors. Additionally, there were five rockets made from cardboard, two from fiberglass, and one made of polystyrene. These different design aspects were input into OpenRocket to simulate the expected performance of each rocket. On launch day each rocket was equipped with altimeters that were able to collect the flight data, which was then compared to the simulation to analyze how well the rockets performed compared to their expected performance. Based on the diversity of rockets and the execution of the team on launch day, the team finished second overall in the competition.

Study on heat exchanger structural optimization of stationary engine thermoelectric generator system

Thermoelectric generators have received considerable involvement in recovering the wasted heat from internal combustion engines (ICE). However, the power of the thermoelectric generator system (TGS) on an ICE is minimal compared with the exhaust energy. This study investigates the effects of heat exchanger structural parameters, including the fin quantity, fin height, and fin thickness, on the performance of the TGS utilizing the emission gas from a stationary diesel engine to find the optimal set of parameters that produce the maximum performance. The numerical method is adopted to determine the total output and pressure loss powers of the TGS with various fin quantities, heights, and thicknesses at three engine operating modes. The tradeoff ratio is utilized to compare the performances of different TGS structures to account for their pressure drop effect on engine power reduction. The results reveal that the output power of TGS increases when the fin quantity, thickness, and height rise. However, when the number of fins is large enough, it reduces with the rise of fin height. Pressure loss increases with the increasing fin quantity and thickness but decreases with increasing fin height. The set of optimal parameters found in this work is the heat exchanger with 28 fins, a fin height of 40 mm, and a fin thickness of 1 mm. Thanks to the optimal heat exchanger, the TGS output power increased to 45.39% compared with the worst case in the considered range. This optimization is necessary because it achieves the highest performance and makes the TGS more compact and affordable price. This result is the critical basis for designing and manufacturing the TGS prototypes for future experimental studies.

Close-contact melting and natural convection in unconstrained melting: A parametric study

Close-contact melting (CCM) is a phenomenon that can be achieved in latent thermal energy storage (LTES) units where the falling of solid PCM is realized. On the other hand, natural convection (NC) plays an important role in LTES units due to circulations based on the buoyant flow of liquid phase change material (PCM). However, the relative contribution of CCM and NC on the melting heat transfer remains unclear when they coexist. This study considers a set of parametric cases that numerically investigate the effects of CCM and NC on an LTES unit with annular fins where CCM is enabled with a shell made of aluminum heated by the heat transfer fluid (HTF). The enthalpy-porosity method is used to model the melting in the LTES unit, and it is established that CCM can be realized using this method with a small value of mushy zone constant. However, with this small value, the mushy zone turns into a highly viscous liquid. The parametric study considers the number of fins and their clearance and concludes that with a decrease in fin clearance and an increase in fins, the effects of CCM are boosted, resulting in faster melting. The behavior of CCM and NC are characterized using the transient behavior of heat transfer rate for different surfaces and defining a factor that calculates the contribution of each surface on the melting. The role of CCM in the melting is up to 50%, while NC plays a less significant role. This study helps with the design of LTES units where CCM is enabled.

Optimizing fin design for enhanced melting performance in latent heat thermal energy storage systems

The addition of fins to phase change material (PCM) in latent heat thermal energy storage (LHTES) systems is a widely employed technique to enhance thermal performance and significantly improve energy storage efficiency. This research focuses on a two-dimensional numerical model investigating heat transfer within a shell-and-tube structure of LHTES. Various combinations of fin number and fin height were explored to assess their influence on melting performance while maintaining the consistent fin volume. Subsequently, a topology optimization technique was developed to determine the most effective fin configuration. The optimized fins exhibited dendritic distributions and outperformed other fin designs in terms of heat transfer performance. The topology-optimized design resulted in a remarkable 74 % increase in melting performance compared to the structure without fins. Furthermore, we introduced a simplified model that takes into account manufacturing feasibility. We verified that a fin volume fraction of 6 % resulted in a significantly reduced melting time of 36 min, in stark contrast to the 249 min observed without fins.

High temperature transcritical CO2 heat pump with optimized tube-in-tube heat exchanger

CO2 heat pump operating on tanscritical cycle is widely adopted to provide hot water whose temperature is as high as about 90 °C. Recently, it is recognized that high temperature heat pump has promising application in various industries such as papermaking, chemical, automotive, and metallurgical. Then, in this paper a model of a tube-in-tube heat exchanger was established, and its parameters including tube length, fin height, fin number, fin thickness and helix angle are optimized through simulation to enhance its heat transfer performance, Accordingly, a transcritical CO2 heat pump system which can provide about 100 °C pressurized hot water is proposed and investigated. Subsequently, an experimental setup is constructed and operated under ambient temperatures, inlet and outlet temperatures of cooling water to demonstrate the feasibility of obtaining hot water at 100 °C. When the ambient temperature and inlet water temperatures are 40 °C and 9 °C respectively, the highest COP of 3.64 is obtained in experiments and the corresponding simulated value is 3.87. When the ambient temperature is 40 °C, inlet and outlet water temperatures are 9 °C and 85 °C, respectively, the study recorded the highest COP of 4.47. It is worth noting that both the heating capacity and COP increase with rising ambient temperature.

Computational fluid dynamic analysis of an adsorption-based cogeneration osmotic heat engines with stepwise porosity distribution

Adsorption-based osmotic heat engines offer an alternative way for converting ultra-low temperature waste heat into electricity. Here, considering the heat and mass transfer characteristics in the adsorbent bed, a computational fluid dynamic model is developed to describe the adsorption-based osmotic heat engine for power and refrigeration cogeneration. Impacts of the porosity distribution, adsorption time, switching time, fin number and working solution-adsorbent pairs on system performance are comprehensively analyzed under different porosity distribution configurations. Results reveal that Configuration I leads to higher coefficient of performance (COP), exergy efficiency. However, Configuration II renders higher electrical efficiency. Compared with the uniform porosity configuration, COP and exergy efficiency are respectively elevated by 1.96% and 1.19% under the stepwise porosity configuration of 0.3–0.5. The electrical efficiency is increased by 15.5% with porosity configuration of 0.7–0.2. LiCl and AQSOA-Z02 under the stepwise porosity configuration of 0.7–0.2 can lead to the highest exergy efficiency of 7.76%.

Thermal storage performance of latent heat thermal energy storage device with helical fin under realistic working conditions

Latent heat thermal energy storage has garnered increasing interest and development as a significant technique for recovering waste heat. In this research, the latent heat thermal energy storage device with helical fin is proposed and its thermal storage performance is also investigated by numerical simulation. First, assorted helix pitches (400 mm, 200 mm, 100 mm and 50 mm) and fin numbers are taken into account to investigate the thermal storage performance with various fin parameters. Then, four types of nanoparticles (SiC, TiO2, CuO and Al2O3) are dispersed into the phase change material to address the inherent defect of poor thermal conductivity of phase change material. Afterwards, several realistic working circumstances, including four inclination angles (θ = 0°, 30°, 60° and 90°) and eight oscillating inlet temperatures among which the frequencies are 1 Hz, 2.5 Hz, 5 Hz and 10 Hz, and amplitudes are 0.25, 0.5, 1 and 2, are selected to explore the impact on melting process. The results indicate that shortening helix pitch and increasing fin number can accelerate the melting rate, while the selection of these two parameters needs to consider the thermal storage performance and the processing difficulty as a whole. Furthermore, the selection of nano phase change materials needs to balance the relationship between thermal storage rate and capacity. Compared to the complete melting time when the device is placed vertically, the complete melting time is reduced by 14.3% when the device is placed horizontally. Utilizing the oscillating inlet temperature reduces the complete melting time by at least 21.2% compared to using the steady inlet temperature. When the frequency value is increased from 1 to 10, the complete melting time is only reduced by 3.4%. Complete melting time of the amplitude of 2 is 12.9% shorter than that of the amplitude of 0.25.

Heat transfer enhancement and pressure loss analysis of hydrogen-fueled microcombustor with slinky projection shape channel for micro-thermophotovoltaic system

Micro thermophotovoltaic (MTPV) system, as a type of micro-combustion power system, possesses several advantages, including higher energy density, sustained and stable energy output, and significantly extended service life. The energy conversion performance of the MTPV system is known to be closely correlated with the thermal performance of the microcombustor. This study proposes a unique microcombustor for the MTPV system with a slinky projection form channel. The influence of the amplitude of the slinky projection, the slinky projection fins number, and the basic oscillating channel radius on the external wall temperature, temperature uniformity, and pressure loss are investigated by adopting the detailed hydrogen/air reaction mechanism with 3-D numerical models. The results show that the increase of the slinky projection amplitude and the slinky projection fins number can improve the external wall temperature. Compared to the traditional microcombustor, the average external wall temperatures of the microcombustor with a slinky projection amplitude of 0.4 mm are 31.6 K lower at an input velocity of 5 m/s. Additionally, when the input mixture velocity is 5 m/s, the average outer wall temperature improves by 29.4 K as the number of slinky projection fins grows from 10 to 42, and the pressure drop increases by 1.4 times. Furthermore, the basic oscillating channel radius is suggested to be 1.5 mm. In summary, this research provides a valuable method for enhancing the energy production of the MTPV system.

Mathematical Modeling of Pseudoplastic Nanofluid Natural Convection in a Cavity with a Heat-Generating Unit and Solid Finned Heat Sink

The power-law nanofluid natural convection in a chamber with a thermally generating unit and a solid ribbed structure has been studied in this work. A mixture of carboxymethylcellulose with water and copper nanoparticles is a working fluid illustrating pseudoplastic properties. The effective properties of the nanoliquid have been described by experimental correlations reflecting the temperature effect. The governing equations have been formulated on the basis of the conservation laws of mass, momentum and energy employing non-primitive parameters such as stream function and vorticity. The defined boundary value problem has been worked out by the finite difference technique using an independently developed calculation system. The Rayleigh number is fixed for analysis (Ra = 105). The paper analyzes the influence of the nanoparticles volume fraction, an increase in which reduces the temperature in the case of the one edge presence. An analysis of the rib height has shown that its growth leads to a weakening of the convective heat transfer, but at the same time, the source temperature also decreases. Increasing the number of fins from 1 to 3 also helps to reduce the average temperature of the heat-generated element by 15%.

Performance enhancement of photovoltaic solar collector using fins and bi-fluid: Thermal efficiency study

This work exhibits a three-dimensional numerical investigation of a solar collector Photovoltaic Thermal (PV/T) bi-fluid based on the use of dual exchangers cooling with both water and air simultaneously. The effect of the absorber plate design and water mass flow rate (mf) of water and natural airflow has been studied according to the fins added to the system, which mainly includes a flat plate of aluminum attached to the tubes of aluminum. The objective is to analyze the effects of water mf fluctuating between 0.01 and 0.02 kg/s, fins location and number (from 20 to 40 fins), and changing solar irradiation values (100 to 1050 W/m2) on the flow structure and thermal efficiency of photovoltaic solar cells. The hybrid collectors studied are made of monocrystalline photovoltaic cells and an absorber plate of aluminum in the lower of the PV module. An evaluation was made between three configurations of bi-fluid (air and water) PV/T manifolds according to the number of fins. The first configuration is a hybrid PV/T system containing tubes without fins. The second configuration is a hybrid PV/T system containing tubes attached with 20 fins. The third configuration is a hybrid PV/T system containing tubes attached with 40 fins. The results confirm that the thermal efficiency of the PV/T system using (water and air) as a working fluid increase with increasing the number of fins (from 20 to 40 fins) and with increasing solar radiation (100 to 1050 W/m2), but it decreases a little with increasing mf of water (0.01 to 0.02 kg/s) by about 1.1%. For the mf of water equal to 0.01 kg/s, the thermal efficiency of the PVT system configurations 1, 2, and 3 are equal to 50.54%, 52.33%, and 54.25%, respectively. The optimal design for good cooling of the photovoltaic cells and higher yields of the hybrid collector is the third configuration with a water mf of 0.01 kg/s.

Optimizing and using AI to study of the cross-section of finned tubes for nanofluid-conveying in solar panel cooling with phase change materials

This study numerically investigated the effect of applying different shapes of nanofluid-conveying pipes on a thermal solar panel system. Two pipes with circular, elliptical, and square shapes were employed in this system. Likewise, paraffin wax Phase Change Material (PCM) was used in the solar thermal panel. A large number of spherical pin fins were installed over the pipes inside the PCM. The two phases of the NF were simulated, and all equations were solved using an element-free Galerkin method based on weak form. The results showed that the elliptical pipes increased the volume of the liquid PCM around them, while the circular pipes raised the quantity of solid PCM around them. That is to say, these two pipe types brought about the maximum difference in the volume of the phase change material (5%). When t = 2000 s, the temperature could decrease by >1% through circular rather than elliptical pipes. In the same period, the heat transfer rate of the circular pipes was 16.17% above that of elliptical pipes, whose heat transfer was 48.43% higher compared to the square pipes. When the solar panel was hot, elliptical pipes maximized the temperature of the output NF, and circular pipes minimized the NF's temperature at the outlet.

Experimental study on performance improvement of a household refrigerator with a flying-wing evaporator

In order to improve the performance of a household refrigerator, a flying-wing evaporator (FWE) is to replace the original finned tube evaporator (FTE). Different from the FTE, the fins of the FWE are formed directly on the tube by shoveling movement. Therefore, the FWE has high efficient heat transfer performance due to no thermal contact resistance between the tubes and the fins. According to different combinations of fin pitch and number of tube rows, three different structures of FWE are designed and tested in comparison with the original FTE on a double-door household refrigerator. The results show that the FWE shortens the cooling duration by 0.32 h (9.3%) and reduces the annual energy consumption by 4.28% with a 25% reduction in volume and a 13.5% reduction in refrigerant charge. This study proves that applying a FWE into a household refrigerator instead of the traditional FTE is one of the effective ways to decrease the volume of evaporator, reduce the energy consumption of refrigerator and enhance the effect of food preservation.

Mass Flow Function Correlation for Solid and Honeycomb Land Labyrinth Seals including Fin Front Angle, Clearance, Fin Number and Honeycomb Geometry

In this study, the effects of several geometry factors (fin front angle, clearance, number of fins, and honeycomb cell diameter and depth) on the mass flow function of solid and honeycomb land were studied experimentally. The fin front angle considered in the experiment ranged from 60 to 90 degrees, the number of fins was varied between two and three, and the diameter and depth of the honeycomb cell ranged from 1.33 to 4.00 times and 8.08 to 13.08 times the thickness of the fin tip, respectively. The experimental results showed that the mass flow function decreased as the number of fins increased for the solid land labyrinth seal, and the mass flow function increased as the clearance increased. A fin front angle of 60 degrees was found to have the minimum mass flow function. For the honeycomb land labyrinth seal, the mass flow function decreased as the number of fins increased, and the effect of the cell depth was shown to be insignificant compared to the effect of the cell diameter. The effects of cell diameter and cell depth on the mass flow function depended on the conditions of other variables. In addition, the correlation equations of the mass flow functions of the solid land and honeycomb land labyrinth seals are presented based on the experimental results, which represent the effects of the fin front angle, clearance, pressure ratio, and diameter and depth of the honeycomb cell. The correlation equation for the solid land labyrinth seal had an r2 value of 0.9822, while the correlation equation for honeycomb land had an r2 value of 0.9621.

Response Surface Method Approach for Optimizing Roasting Condition in Robusta Coffee Cupping Test Quality

The Roasting process was an important step to generate good-quality roasted coffee beans. Two factors that affected coffee bean perfection were roasting time and temperature. An appropriate time and temperature will emphasize the greatest coffee bean aroma, color, and flavor, while the speed of the roasting process depends on the number of stirring fins in a roasted machine. The purpose of this study was to optimization time, temperature, and stirring fin number in the roasting process to generate the best cupping test roasted coffee beans. The Central Composite Design (CCD) was used in this study to determine Response Surface model. Minitab 17 and Design Expert 4.0 software used to determine the combination for all variables. Robusta green bean was taken from Kota Agung Timur, Lampung, which had density of 701—750 g/L. The result recommended roasted coffee bean was at 213oC for 16.7 minutes and used 3 stirring fins. This condition will generate cupping test score 84.92 which is define as Excellent in score notation criteria. CCD methods has develop an equation from optimal process to predict roasted coffee bean cupping test quality i.e., Y = 85.6 – 0.0088X1 – 1.2X2 – 11.06X3 + 0.000043X12 – 0.038X22 – 0.70X32 + 0.01000X1X2 + 0.0625X1X3 + 0.300X2X3. Keywords: Cupping test, Response surface model optimization, Robusta coffee bean.