Composite Fin Research Articles

Flutter Optimization of Carbon/Epoxy Plates Based on a Fast Tree Algorithm

This study focuses on optimizing carbon/epoxy laminate configurations to maximize the flutter speed of composite structures using a Fast Tree Regression algorithm. Initially, a seed dataset was created, using finite element method (FEM) modal analysis for common stack-ups used in composite fins and UAV components. The FEM analysis, based on the Lanczos algorithm for extracting modal frequencies in bending and torsion, was verified through experimental modal analysis using an AS-4/3501-6 composite system. Custom software was developed to interface with the FEA modal software, enabling the generation and augmentation of laminate dataset scenarios. The seed dataset was expanded until the coefficient of determination (R2) reached at least 0.95. Various regression algorithms, including Fast Forest Regression, Fast Tree Regression, Sdca Regression, and Lbfgs Poisson Regression, were evaluated. The Fast Tree Regression algorithm was selected for further analysis due to its superior performance. This algorithm was applied to a design space of nearly 2000 potential laminate candidates, focusing on symmetric lay-ups to avoid undesirable coupling between bending and torsion in UAV and missile control surfaces. The final optimized lay-ups, exhibit the highest Delta function values (the squared difference of modal frequencies in torsion and bending), indicating the expected highest flutter speeds. The results demonstrate the efficacy of tailored composite materials in achieving specific aerodynamic performance goals.

Dynamic hydroelasticity of composite appendages with reverse-mode algorithmic differentiation

Composite materials enable the tailoring of load-dependent, passive, shape adaptation because of the directional stiffness of the fibers. However, excessive flow-induced vibrations and dynamic instabilities represent a design challenge for composite marine appendages. We develop DCFoil, a dynamic composite foil solver that uses one-dimensional models—composite beam elements and unsteady lifting line theory—to perform static and dynamic frequency domain analysis. The program is differentiated to provide derivatives of an aggregated flutter function with respect to design variables. The flutter function characterizes dynamic hydroelastic stability. We apply the solver to investigate the hydroelastic performance of a composite fin bulb keel based on the IMOCA 60 class of racing yachts, which were reported to have flutter problems. Based on the derivatives computed for this bulb keel, we found that the foil thickness has the most significant impact on flutter speed. This work shows both the development of and utility of a program with flutter derivatives for flexible composite marine appendage design.

Continuous composite longitudinal fins under oscillating boundary conditions: a lattice Boltzmann solution

PurposeTransient response of continuous composite material (CCM) fin made of high thermally conductive composite material is presented. The continuously varying effective properties of composite material such as thermal conductivity, heat capacity and density have been modelled using the Mori-Tanaka homogenization theory and rule of mixture. Additionally, temperature dependency of thermal conductivity, heat generation (composite materials) and convection coefficient (fluid properties) have also been incorporated. Different base boundary conditions are addressed such as oscillating heat flow, oscillating temperature, step-changing heat flow and step-changing temperature. At the other boundary, the fin is assumed to have a convective tip.Design/methodology/approachLattice Boltzmann method is implemented using an in-house source code for obtaining the numerical solution of typical non-linear heat balance equation of the aforementioned problem under various transient base boundary conditions.FindingsThe effects of various thermal parameters such as material diffusivity ratio and conductivity ratio, area ratio and Biot number on transient response of fin and temperature distribution of fins are studied and interpreted. The heat transfer rate and time for attainment of steady state temperature of metal matrix composite (MMC) fin are found to be proportionally dependent on their diffusivity ratio. Additionally for higher values of area ratio and biot number, MMC fins are reported to dissipate the heat more efficiently in comparision to homogeneous fins in terms of time required to attain the steady state and surface temperature.Practical implicationsResponse of transient fin associated with advanced class of material can facilitates the practicing engineers for designing high-performance and/or miniaturized thermal management devices as used in electronic packaging industries.Originality/valueStudies of composite fin consisting of laminating second layer of material over the first layer have been reported previously, however transient response of CCM fin fabricated by continuously varying the volume fraction of two materials along the fin length has not been reported till date. Such material finds its application in thermal management and electronic packaging industries. Results are plotted in form of a graph for different application-wise material combinations that have not been reported earlier, and it can be treated as design data.

Effect of composite fin structure on phase change heat storage tank: A numerical investigation

This study investigates the phase change heat storage process in the hot water displacement system. The PCHS unit incorporates V-shaped fins and straight fins to enhance heat transfer, with the additional enhancement of annular fins. Numerical simulation is used to examine the impact of fin structure and quantity on the evolution of internal flow rate, liquid phase, and temperature during the heat charging process. The response of different fin structures to parameters such as melting time, heat storage rate, storage capacity, and dimensionless temperature is analyzed. The results indicate that Model-6 (4 V-shaped fins + annular fins) exhibits the shortest melting time, reduced by 52.13 % compared to Model-1 (initial structure). The melting time of Model-4 (4 straight fins + annular fins) and Model-6 shows little difference, during the final melting stage, attributed to the good heat transfer performance of the bottom fin in Model-4. Furthermore, the total heat absorption of Model-4 and Model-6 is decreased by 3.92 % and 3.20 % respectively compared to Model-1, while the mean rate of heat storage is increased by 100.20 % and 102.21 % compared to Model-1, demonstrating the significant improvement in heat storage performance with annular fins. Additionally, the same number of V-shaped fins and straight fins, when paired with annular fins, exhibit minimal differences in their strengthening effects, with V-shaped fins enhancing pre-melting and mid-melting, and straight fins showing advantages for end-melting.

Enhancing automotive cooling systems: composite fins and nanoparticles analysis in radiators

Composites are driving positive developments in the automobile sector. In this study investigated the use of composite fins in radiators using computational fluid dynamics (CFD) to analyze the fluid-flow phenomenon of nanoparticles and hydrogen gas. Our world is rapidly transforming, and new technologies are leading to positive revolutions in today’s society. In this study successfully analyzed the entire thermal simulation processes of the radiator, as well as the composite fin arrangements with stress efficiency rates. The study examined the velocity path, pressure variations, and temperature distribution in the radiator setup. As found that nanoparticles and composite fins provide superior thermal heat rates and results. The combination of an aluminum radiator and composite fins in future models will support the control of cooling systems in automotive applications. The final investigation statement showed a 12% improvement with nanoparticles, where the velocity was 1.61 m/s and the radiator system’s pressure volume was 2.44 MPa. In the fin condition, the stress rate was 3.60 N/mm2.

Thermal analysis of modified segmented switched reluctance motor with aluminium metal matrix composite fins used in cooling fan applications

Thermal analysis of modified segmented switched reluctance motor with aluminium metal matrix composite fins used in cooling fan applications

Composite Fins Subsonic Flutter Prediction Based on Machine Learning

In the present work, the potential application of machine learning techniques in the flutter prediction of composite materials missile fins is investigated. The flutter velocity data set required for different fin aerodynamic geometries and materials is generated using a hybrid data collection method: from the wind tunnel experiments at flows ranging from 5 to 30 m/s at Re = 300,000 to 500,000, whereas synthetic data is collected using modified NACA flutter boundary model. Once the flutter data are collected, different regression algorithms were investigated, and the results were compared in terms of accuracy (when compared to the experimentally obtained results and the numerical flutter models), training time (minimization), and R-squared values (maximization). The algorithms investigated and their performance analyzed are fast forest regression, SDCA regression (stochastic dual coordinate ascent), and the light GBM (light gradient boosting machine) regression algorithm that belongs to the gradient boosting regression algorithm family. It was found that the light GBM algorithm renders the most accurate results. Based on this research, it can be concluded that artificial intelligence (machine learning) techniques can be successfully deployed in the analysis of complex flutter phenomena.

Numerical investigation of the melting characteristics of spherical-encapsulated phase change materials with composite metal fins

A spherical phase change material (PCM) capsule with embedded composite fins for latent thermal energy storage is proposed and studied in this paper. A three-dimensional numerical model is established and validated by comparing with experimental data in the literature. The influences of the embedded fins with different structures, capsule size, and heating temperature on the melting performance are analyzed. Results show that the insertion of composite metal fins promotes the melting process owing to the extension of thermal surface. The fin with perforations exhibits higher energy storage performance as compared to the non-perforated one, which can be attributed to the reduction of the blockage effect as well as the increment in the filling volume of PCM. The punched fin with three perforations in each sheet is preferable to adopting in spherical PCM capsule in view of the less time required for completely melting and the higher energy storage capacity. However, as the size of capsule increases, the heat transfer enhancement contributed by the inclusion of the embedded fins reduces. In addition, the melting process can be accelerated significantly by raising the temperature of external shell surface from 340 to 360 K, while such improvement tends to be less pronounced for the further increase in heating temperature. This study can provide useful guidance for the optimal design of thermal energy storage system with spherical PCM capsules.

STAJe−: A Supersonic Flight Program STAJe− 1 Payload Design and System Study

The STAJe− flight program is the latest implementation of a university-based supersonic and hypersonic flight-test program. In the first flight, which is the subject of this study, the focus is on evaluating the suitability of commercial off-the-shelf electronic hardware, additively manufactured internal payload structures, and a long-range communications technique in the challenging environment presented by flight at high supersonic Mach numbers. These items can significantly reduce the cost of a flight experiment, and thus lower the threshold for flight experimentation. The scientific objectives of this flight are to collect pressure and temperature data on the whole trajectory to compare to numerical models, to optically measure the temperature of composite fins mounted on the payload, and to eject the flight module from the rocket assembly and track its location for subsequent recovery. Design calculations for the tracking system are presented alongside experimental results from ground tests demonstrating the suitability of the system. Furthermore, a one-dimensional calculation of the external wall temperatures over the trajectory is presented, which shows that internal systems are sufficiently protected from the harsh environment. Although the materials are shown to be appropriate for the flight, a layer of cork will be added to parts of the payload to further reduce the chance of structural failure. In addition, it is shown that a pneumatic ejection system is suited to overcoming the drag forces on the front of the rocket to initiate separation.

Thermal management of lithium-ion battery pack under demanding conditions and long operating cycles using fin-enhanced PCMs/water hybrid cooling system

A fin-enhanced hybrid cooling system combining phase change material (PCM) and liquid cooling is designed and optimized in this work to ensure the stable operation of lithium-ion battery under high ambient temperature, high discharge rate or long operating cycles, which is a challenging and burning issue. The coupling effects of composite PCM, fin arrangements, cooling water inflow schemes, and ambient temperature on the heat dissipation performance of battery pack are numerically studied. The maximum temperature can be reduced by up to 7.66 °C with expanded graphite modified PCM at 5C discharge rate and 40 °C ambient temperature, and the optimal mass fraction is found to be 12–16%. The arrangement of composite fins and two-layer PCM can further improve adaptability with better temperature control or temperature uniformity, and the suitable ranges of ambient temperature, coolant inlet temperature and velocity for safe operation are obtained. In general, the hybrid cooling system with fins and counter flow can be used for the thermal management design of batteries used at high temperature of 40 °C and high discharge rate of 5C, and the temperature and temperature difference can be controlled to within 46.2 °C and 4.2 °C respectively. The hybrid cooling system also offers a reliable cooling performance during 2C rate of charging and discharging cycle process, and the temperature and temperature difference can be controlled below 42.2 °C and 1.7 °C respectively.

Air-side thermal-hydraulic analysis and parameter optimization for vertical-fin microchannel heat exchanger

The vertical-fin microchannel heat exchanger (VMHX) has efficient thermal-hydraulic performance and favorable drainage performance, which is capable to be utilized in the air source heat pump under wide operating conditions. In this article, CFD is employed to analyze the air-side thermal-hydraulic performance of VMHXs under dry conditions. The model is verified by experimental results with an error of less than 20%. Then, the sequence and connection of wave and louver on composite fins are compared, while the effects of fin pitch, fin length, tube pitch, and fin thickness are investigated. Finally, parameter optimization is conducted by Taguchi method. Results show that under the same pump power, the heat transfer enhancement of the fin with front louver and rear wave connected reversely is the best. When the comprehensive index performance evaluation criteria (PEC) is used as performance evaluation of VMHXs, the tube pitch and fin length are the main factors. Within the range of parameters practically available, the best performance is obtained by the combination of 1.8 mm fin pitch, 25.6 mm fin length, 12.0 mm flat tube pitch, and 0.12 mm fin thickness.

Experimental and numerical investigation of longitudinal and annular finned latent heat thermal energy storage unit

The melting process of phase change material (PCM) in horizontal latent heat thermal energy storage (LHTES) units with longitudinal and annular fins was experimentally studied under the same fin volume condition. The PCM melting time of the annular fin unit is reduced by 13.7% compared to that of the longitudinal fin unit. The annular fins are more responsive to the increase in heat transfer fluid (HTF) inlet temperature and the longitudinal fins are more responsive to the increase in HTF flow rate. After that, numerical studies were also performed for the two LHTES units to reveal in-depth the differences in heat storage processes. The results show that the longitudinal fins perform better in the early stage due to their larger contact area with the inner tube and a denser distribution near the inner tube. But it also limits the natural convection in the latter stage. The annular fins have better natural convection performance in the latter stage and therefore have better heat storage performance. Based on the analysis, a composite fin was designed to combine the advantages of longitudinal and annular fins. Numerical results show that the newly designed fin results in a 21.6% melting time reduction compared to the longitudinal fin model and a 9.5% melting time reduction compared to the annular fin model. Finally, two principles to guide the fin design in horizontal shell-and-tube LHTES units were summarized.

Analiza flatera kompozitnih trapeznih repnih površina - analiza i eksperiment

In the present work, the aeroelastic stability of tapered composite plates is investigated. Existing flutter models, based on the typical section approach, are reviewed for quasi-steady and unsteady low Mach number axial flows and modified for the thin composite tapered plates. The numerical approach, based on panel vortex methods for flutter analysis, is presented, and results are compared to typical section flutter methods for the tapered composite fins. Experimental work is performed in the subsonic wind tunnel at flow speeds of 20 - 30 m/s range. Good agreement between experimental, analytical, and numerical results is obtained, and it was concluded that the presented methodology could be used for estimating the flutter boundary velocities for the composite thin flat plates.

Solidification performance enhancement of encapsulated ice storage system by fins and copper foam

It is critical for the encapsulated ice storage system to maintain high cooling capacity within permissible time. In this paper, the strengthening effects of metal foam and fins on ice storage spheres are numerically studied comprehensively. The variations of the temperature field, ice front evolution, solidification fraction, total solidification time and the cold storage capacity are analyzed under four different strengthening configurations (plain, fins, metal foam and metal foam composite fins). The optimum porosity is obtained after the comparison of four comprehensive criteria about the input-output performance. Finally, the dimensionless parameters of the metal foam ice storage sphere are analyzed. The results demonstrate that the temperature distribution in the metal foam ice storage sphere is more uniform, and the solidification rate is faster due to coupled effects of thermal conduction enhancement and the suppression of the natural convection. Metal foam composite fins can remarkably save 83.5% of the solidification time and enhance the solidification rate by 6.1 times compared with the non-enhancement case. Dimensional analysis of the results is presented as the solidification fractions versus an appropriate combination of the porosity, Fourier, and Stefan numbers. Compared with the previous non-metal foam prediction formula, the formula reported in this research is more accurate. The prediction accuracy can improve by 20%.

Development and actuation analysis of shape memory alloy reinforced composite fin for aerodynamic application

In this investigation, a shape memory alloy (SMA) based aerodynamic composite Fin has been developed. In general, the missile fins play a crucial role in changing the direction of a conventional missile using motor arrangement. Therefore, SMA-based composite Fin might be a promising alternative to control the direction without using the motor. The composite Fin is made of laminated fiber polymer and SMA wire. Initially, rectangular composite structures have been developed with different wire prestraining percentages, lengths, diameters, and configurations to understand their electrical actuation behavior. Based on the experiments, optimized parameters have been derived and applied to the composite fin. Adaptive composite actuation was performed via selective joule heating on the composite fin. Under optimized conditions, SMA-based composite structure shows maximum displacement of 65 mm with a maximum angle of 60 degrees before failure, where the diameter of 5 % pre-strained SMA wire was 0.5 mm at 6 % of SMA to Composite ratio (volume of SMA/volume of composite). Maximum displacement and failure analysis of the composite structure has been analyzed at optimized parameters.

Natural convection of Al2O3-water nanosuspension in a semi-open domain with composite fin

Development of modern electronic devices and heat exchangers is related to the energy transport intensity. For this purpose, it is possible to use the internal fins and nanofluids. The present study is devoted to mathematical simulation of free convective thermal transmission of alumina-water nanoliquid in a semi-open cavity with the complicated fin including the wall-mounted part and internal obstacle. Analysis has been carried out by means of the partial differential transport equations written on the basis of the non-dimensional, non-primitive variables. The special procedure has been developed for description of the stream function value at the body surface within the cavity. The developed code has been validated using the mesh sensitivity analysis and computational results of other researchers. Impacts of the Rayleigh number, internal obstacle position, and nano-sized particles concentration on nanoliquid flow and thermal transmission have been considered. It has been revealed that for the present formulation a growth of the solid particles concentration results in the heat transport degradation, while it is possible to find an optimal position of the inner body for the energy transport intensification.

Evaluation of Convective Heat Transfer Coefficient and Heat Transfer Rate through Aluminium Metal Matrix Composite Fin made by Stir Casting

The pure metals are having their benefits and shortcomings. Some were having good ductility, some having good strength and some were having good thermal properties. If we were in a need of all these properties together it would occupy more space, more cost, and add additional weight to the product. To overcome all these problems, worked on Aluminium Metal Matrix. For this process, considered copper as reinforcement to the Aluminium base metal matrix. Aluminium Metal Matrix composite is produced by using the Stir casting method, which is the easiest and cost-effective method. Produced composite material with different compositions of reinforcement (Plane, 5% Cu, 10% Cu and 15% Cu) to Aluminium base Matrix. For each composition, found the values of thermal properties experimentally analyzed the variation of all properties concerning the change in the composition of copper material.

Numerical analysis of rectangular fins with circular perforations

Fins have long been used as heat transfer augmentation devices. Fins are made from a range of metals such as mild steel, stainless steel, aluminium, silver, and copper. As fins (extended surfaces) technology advances, new design concepts such as composite fins, porous materials, interrupted and perforated plates have arisen. Fin size optimization is critical owing to the increased requirement for compact, small, and cost-effective fins. As a result, fins must be engineered to extract the maximum heat with the least amount of material while still taking into account the fin's ease of production. The increase in heat transfer coefficient can be attributed to a variety of factors. The resetting of the thermal boundary layer with each disturbance is associated with the enhancement in heat transfer coefficient. Surface interruption can be seen in the form of perforated plates in fins. The objectives of this report is to estimate the temperature reduction across a number of circular perforations. Other variables such as heat flux and thermal gradient are contrasted over a spectrum of circular perforation counts. This analysis is carried out by using ANSYS Fluent code. It was found that there was an appreciable temperature drop and an enhancement of heat transfer using circular perforations. The study can be used in the design of heat exchangers employing rectangular fins.

Various Intensification methods for Adsorption-a review on studies and investigations

Adsorption is used for removal of pollutants and waste gases from liquid and gases effluent. Use of waste material for adsorption preparation makes this method more attractive. Regeneration of this adsorbent is very important aspect of the application of adsorption for various applications. Intensification of the adsorption bed includes reducing cycle time for pressure swing (PSA) and temperature swing (TSA) adsorption increasing thermal conductivity of the bed, optimizing various operating parameters. Regeneration of bed is an important aspect in adsorption desorption cycle as the low thermal conductivity of adsorbent is responsible for extended cycle time. To increase the conductivity, conducting materials in the form of composite fins can be uses. This review aims to study of different intensification technique for adsorption desorption process.

ИССЛЕДОВАНИЕ УСТОЙЧИВОСТИ ДВИЖЕНИЯ И ВЫНУЖДЕННЫХ КОЛЕБАНИЙ СОСТАВНОГО ПЛАВНИКОВОГО ДВИЖИТЕЛЯ

The motion equations of flapping elements of composite fin propulsion system were derived using Vittenburgs approach. These equations were linearized and used in the development of mathematical model which is capable of analysis of stability of motion and forced oscillations of such constructions in liquid flow. Critical flow velocity was calculated using numerical simulation: motion of considered configuration of composite fin propulsion system becomes instable for cases corresponding values of flow velocities above critical. Forced oscillations analysis of the construction reveals that maximum of amplitudes of related elements appears when operating frequency of main elements oscillations coincides with composite fin propulsion system natural frequency. This case seems to be the most interesting for further exploration with actual CFD methods for calculating hydrodynamic and propulsive characteristics of the propulsive system.