Effect Of Inclination Angle Research Articles

Additive manufacturing of metal-polymer hybrid parts: the influence of as-printed LPBF surface roughness on the joint strength

As-printed Laser-Powder Bed Fusion (LPBF) surfaces can provide anchoring spots for the infiltration of polymer printed by Fused Filament Fabrication (FFF), enhancing metal-polymer joint strength. This work evaluates the influence of the as-printed LPBF surface roughness and FFF parameters on the strength of Ti-6Al-4V/PA-CF joints produced by this process combination. A three-point bending testing method based on ISO 14679:1997 was deployed, whereby the energy dissipated by the joint interface was measured. Roughness was varied by 3D-printing the substrate with different inclination angles; Height and printing speed of the coating layer (the polymer layer in direct contact with the metal) were also varied. Data was interpreted using a combination between Decision Tree and Gradient Boosting Regression, ultimately suggesting that printing speed is the prominent parameter followed by inclination angle for joint strength. Additionally, the combined effect of low printing speed and inclination angle resulted in the highest energy absorption at the interface (>200 J).

Exergy Analysis of a Shell and Tube Energy Storage Unit with Different Inclination Angles

To optimize the utilization of solar energy in the latent heat thermal energy storage (LHTES) system, this study conducts exergy analysis on a paraffin-solar water shell and tube unit established in the literature to evaluate the effects of different inclination angles, inlet temperatures, original temperatures, and fluid flow rates on the exergy and exergy efficiency. Firstly, the thermodynamic characteristics of the water and the natural convection effects of the paraffin change with different inclination angles. When the inclination angle of the heat storage tank is less than 30°, the maximum exergy inlet rate rises from 0 to 144.6 W in a very short time, but it decreases to 65.7 W for an inclination angle of 60°. When the inclination angle is increased from 0° to 30°, the exergy efficiency rises from 86% to 89.7%, but it decreases from 94% to 89.9% with the inclination angle from 60° to 90°. Secondly, under the condition that the inclination angle of the energy storage unit is 60°, although increasing the inlet temperature of the solar water enhances the exergy inlet and storage and reduces the charging time, it increases the heat transfer temperature difference and the irreversible loss of the system, thus reducing the exergy efficiency. As the inlet water temperature is increased from 83 to 98 °C, the exergy efficiency decreases from 94.7% to 93.6%. Moreover, increasing the original temperature of the LHTES unit not only reduces the exergy inlet and storage rates but also decreases the available work capacity and exergy efficiency. Finally, increasing the inlet water flow rate increases the exergy inlet and storage rates slightly. The exergy efficiency decreases from 95.6% to 93.3% as the unit original temperature is increased from 15 to 30 °C, and it is enhanced from 94% to 94.6% as the inlet flow rate is increased from 0.085 to 0.34 kg/s with the unit inclination angle of 60°. It is found that arranging the shell and tube unit at an inclination angle is useful for improving the LHTES system’s thermal performance, and the exergy analysis conducted aims to reduce available energy dissipation and exergy loss in the thermal storage system. This study provides instructions for solar energy utilization and energy storage.

Experimental study of particle deposition on a solar photovoltaic panel based on the response surface method.

To explore the influence of different factors on particle deposition, four crucial factors, including particle size, wind speed, inclination angle, and wind direction angle (WDA), were considered, and the particle deposition concentration was used as the response variable for experimental research. In this paper, the Box‒Behnken design analysis method in the response surface method was used to conduct experiments. First, the element composition, content, morphology characteristics, and particle size distribution of dust particles were analyzed experimentally. The changes in wind speed and WDA were obtained through a month-long test measurement. Then, the effects of particle size (A), wind speed (B), inclination angle (C), and WDA (D) on the deposition concentration were examined utilizing a test rig. The test data were analyzed by using Design-Expert 10 software, and the results show that four factors have different degrees of influence on the particle deposition concentration, in which the inclination angle effect is the smallest. In the two-factor interaction analysis, the P values of AB, AC, and BC are all less than 5%, indicating that the correlation between the two-factor interaction term and the response variable is acceptable. In contrast, the correlation between the single-factor quadratic term and the response variable is weak. According to the analysis results of single-factor and double-factor interactions, the quadratic fitting formula of particle deposition influencing factors and deposition concentration was obtained, which could quickly and accurately calculate the variation trend of particle deposition concentration under different environmental conditions.

Numerical investigation on fracture characteristic and failure mechanism of rock-like materials with intermittent flaws under compressive-shear loading

An extended non-ordinary state-based peridynamic (NOSB-PD) theory is utilized to investigate the fracture characteristics of rock-like materials containing intermittent flaws under compressive-shear loading. The stress-based failure criteria, i.e., the maximum tensile stress criterion and the Mohr-Coulomb criterion, are integrated into the NOSB-PD theory to respectively determine the tensile failure and shear failure of flawed rock-like materials. The distribution characteristics of maximum principal stress and shear stress acquired by the NOSB-PD theory are employed to analyze the fracture failure mechanism of flawed rock-like materials under compressive-shear loading. The effects of inclination angle of the central flaw on the initiation and coalescence modes of flawed rock-like specimens are investigated. The numerical results of flawed rock-like materials are in good agreement with the experimental results. The extended NOSB-PD has the ability to simulate the fracture processes under compressive-shear loading.

Experimental Investigation of Heat Transfer Enhancement in a Double Pipe Heat Exchanger Using Compound Technique of Transverse Vibration and Inclination Angle

Numerous tests are recently conducted to assess vibration's role in accelerating the heat transfer rate in various heat exchangers. In this work, the enhancement of heat transfer by the effect of transfer vibration and inclination angles on the surface of a double pipe heat exchanger experimentally has been investigated. A data acquisition system is applied to record the data of temperatures, flow rates, and frequencies over the tests. A compound technique was adopted, including the application of a set of inclination angles of (0°, 10°, 20°, and 30°) under the effect of frequency of vibration ranging from sub-resonance to over-resonance frequencies. The results showed that the overall heat transfer coefficient enhances by applying the compound technique at all the working fluid's temperatures and flow rate ranges. The maximum increase in overall heat transfer coefficient occurs at an angle of 30° and the resonance frequency. Moreover, the effectiveness of the double pipe heat exchanger gradually expanded when temperature, inclination angles, and vibration amplitude rosed. But the effectiveness value declined as the hot working flow rate increased considerably. Finally, the enhancement factor demonstrated that the combined strategy (vibration frequencies and inclination angles) had been the most effective technique in improving and enhancing heat transfer and was superior to the other ways. Additionally, the extremes improvement in overall heat transfer coefficient, effectiveness, and enhancement factor are 183.4, 191, and 164.4 %. The improvement was situated at the resonance frequency with a 30° inclination angle.

Distal Radius Eklem İçi Kırıklarının El Bilek Fiksatörü ile Tedavisinde Radio-Ulnar Açıdaki Değişikliklerin El Bilek Skorlamasına Etkisi

Aim: This study was aimed to evaluate the effect of radial inclination (RI) angle, assessed with radiological measurement, on the clinical outcomes of intra-articular fractures of the distal radius (IFDR) treated with closed reduction and penning type dynamic wrist fixator. Material and Methods: A total of 120 patients who underwent closed reduction and dynamic wrist fixation due to IFDR between 2012 and 2020 were retrospectively reviewed. The effects of the changes in RI on clinical outcomes according to Mayo wrist scoring (MWS) criteria were investigated by measuring the RI angles in anteroposterior wrist radiographs of the patients at postoperative 2nd, 6th, and 10th weeks. Results: According to the AO fracture classification, 77 (64.2%) of the patients had type C1 and 43 (35.8%) of the patients had type C2 fracture. The patients comprised 69 (57.7%) females and 51 (42.3%) males, and the mean age was 50.08±15.36 years. Fixators were removed at six weeks. RI angles measured at post-op week 10 were 20°-30° in 83 (69.1%) patients, 10°-19° in 32 (26.6%) patients, and 0°-9° in 5 (4.3%) patients. According to MWS, 39 (32.5%) patients were evaluated as excellent, 76 (63.3%) patients as good, and 5 (4.2%) patients as moderate. A statistically significant positive correlation was observed between RI values and MWS (r=0.369, p<0.001). Conclusion: Dynamic wrist fixation with closed reduction is a simple and minimally invasive method, and provides successful clinical and functional results in the treatment of IFDR. We consider that optimal RI angles are effective in clinical and functional outcomes.

Effect of nozzle inclination angle on characteristics of a gas jet in a gas-solid fluidized bed

Changing the incident angle of the nozzle could make the characteristics of the jet such as jet expansion angle (θ), jet width (b), and jet penetration depth (L) change drastically. Experiments were carried out to investigate the effect of nozzle inclination on the jet characteristics in a two-dimensional (2D) fluidized bed of three different particles. The summation method and statistical method are used to extract the θ, bmax, and L from the video data. There is a trend that the penetration of the jet increases with α from −60° to 60°. As the particle diameter and the particle density increase, L and bmax decrease. Considering the variation of force on supported particles at the jet boundary when α ≠ 0°, a penetration model for the inclined jets is proposed. The error between the model prediction value and the experimental value of the L is in the range of −15% ~ 20%.

Numerical Analysis on Water-Exit Process of Submersible Aerial Vehicle under Different Launch Conditions

To study the influence of launch conditions and wave interference on the stability of submersible aerial vehicles at the water–air interface, a coupling model for water-exit motion of submersible aerial vehicles was established by using the RNG k-ε turbulence model and VOF method. The water-exit processes of submersible aerial vehicles under different initial inclination angles and velocities were numerically simulated and the effects of initial inclination angle and velocity on the water-exit motion of submersible aerial vehicles were obtained. Based on the response surface function theory, a mathematical model for the motion stability of submersible aerial vehicles at the water–air interface was established, so that the submersible aerial vehicle’s pitch angle and velocity at the end of vehicle’s water-exit process, corresponding to any initial inclination angle and velocity, can be solved. The deviation between the simulated calculation result and the established fitting function model result was 2.7%. The minimum water-exit velocity of submarine aerial vehicles should be greater than 10.8 m/s. The research provides technical support for the trans-media motion stability analysis and hydrodynamic performance design of the submersible aerial vehicle.

A modified phase-field model for cohesive interface failure in quasi-brittle solids

We formulate a modified phase-field model for cohesive interface failure in quasi-brittle solids. Our model has two novel features: (i) a traction–separation-damage law for damage process; (ii) an energetic degradation function controlled by critical gap ratio. This modification offers an attractive approach to simulate the cohesive interface failure process. We also provide a robust numerical solution strategy to treat the spatio-temporal evolution of cohesive interface failure. Our model is validated by two benchmark problems including the constant strain patch test and mode-I delamination test. The numerical simulations are compared with some published data. We proceed to apply this model to study the complex failure mechanism of a peeling test on bi-material plates and crack impinging on interfaces in different scenarios, where the effects of critical gap ratios and interface inclination angles are discussed.

Discrete element simulation of compression failure mechanism of SiC ceramic considering collinear flaws

A particle-based numerical simulation model was established for SiC ceramics, and a method of deleting the particles along the specified direction was chosen to produce a pair of pre-existing collinear flaws. A serial of simulations were carried out to investigate the effects of inclination angle and ligament length on the failure mechanism under uniaxial compression. The laws of crack initiation and propagation as well as the distribution laws of the stress field and displacement field around the pre-existing flaws were analyzed. The results showed that the influence of inclination angle θ on micro-crack initiation, propagation and coalescence was more significant than that of ligament length L for pre-existing collinear flaws. Meanwhile, three coalescence models can be found with the increase of the inclination angle. By analyzing the evolution process of the displacement and stress fields during the loading process, it was clearly that the first crack was induced by the tensile stress concentration, and the secondary crack was initiated and propagated with tensile and shear stress. Moreover, the propagation mechanism of the micro-crack was closely related to the evolution behaviours of the stress and displacement fields.

Effect of inclination angle on the thermal-hydraulic characteristics and entropy generation of Al2O3–water nanofluid for in-tube turbulent flow

PurposeInclination angle has been reported to have an enhancing effect on the thermal-hydraulic characteristics and entropy of some thermal systems. Therefore, this paper aims to numerically investigate the effects of inclination angle, volume concentration and Reynolds number on the thermal and hydraulic characteristics and entropy generation rates of water-based Al2O3 nanofluids through a smooth circular aluminum pipe in a turbulent flow.Design/methodology/approachA constant heat flux of 2,000 Watts is applied to the circular surface of the tube. Reynolds number is varied between 4,000 and 20,000 for different volume concentrations of alumina nanoparticles of 0.5%, 1.0% and 2.0% for tube inclination angles of ±90o, ±60o, ±45o, ±30o and 0o, respectively. The simulation is performed in an ANSYS Fluent environment using the realizable kinetic energy–epsilon turbulent model.FindingsResults show that +45o tube orientation possesses the largest thermal deviations of 0.006% for 0.5% and 1.0% vol. concentrations for Reynolds numbers 4,000 and 12,000. −45o gives a maximum pressure deviation of −0.06% for the same condition. The heat transfer coefficient and pressure drop give maximum deviations of −0.35% and −0.39%, respectively, for 2.0% vol. concentration for Reynolds number of 20,000 and angle ±90o. A 95%–99.8% and 95%–98% increase in the heat transfer and total entropy generation rates, respectively, is observed for 2.0% volume concentration as tube orientation changes from the horizontal position upward or downward.Originality/valueResearch investigating the effect of inclination angle on thermal-hydraulic performance and entropy generation rates in-tube turbulent flow of nanofluid is very scarce in the literature.

Effect of inclination angle on the film cooling in a serpentine nozzle with strong adverse pressure gradient

The serpentine nozzle is widely used in military unmanned aerial vehicles to improve their viability. The film cooling technology should be used in the serpentine nozzle to cope with excessive thermal load. Strong adverse pressure gradient (APG) in the serpentine nozzle induces the recirculation zone near the upper wall downstream of the film hole, such that the effect of inclination angle on the film cooling characteristics is quite different from that in other studies. A numerical investigation was conducted to study the influence of the film hole inclination angle (α = 20°, 30°, 45°, 60°) on the film cooling characteristics in a serpentine nozzle with strong APG. Results show that the inclination angle changes the region of recirculation zone, then affects the development of counter rotating vortex pair and anti-counter rotating vortex pair (ACRVP), and finally results in different distributions of the film cooling effectiveness (FCE). For blowing ratio, M, = 0.5, 1, and 1.5, with the increase in the inclination angle, the recirculation zone expands, and the vorticity of the ACRVP increases. For M = 2, with the increase in the inclination angle, the recirculation zone first shrinks and then expands, and the vorticity of the ACRVP first decreases and then increases. Taking all the four blowing ratios into account, we find that the 30° inclination angle gives the best film cooling effect, and the area-average FCE under conditions α = 20°, α = 45°, and α = 60° is 7.5%, 5.6%, and 5.0%, respectively, lower than that under condition α = 30°. Therefore, the 30° inclination angle is the optimal choice for the film holes near the APG region of the serpentine nozzle.

Simulation of conductive fins effect on mixed convection heat transfer in a two-dimensional inclined channel using the lattice Boltzmann method

The simulation of the laminar mixed convection heat transfer inside a 2-D inclined channel was investigated here by employing the lattice Boltzmann method (LBM). The channel was equipped with conductive fins. The effects of inclination angle (φ), geometrical parameters (e and A), and a wide range of the Richardson numbers (Ri = 0.1-10) at fixed Reynolds number (Re = 100) on the heat transfer and flow structure were studied. The numerical model was validated by the published benchmark problems. Results were analyzed in terms of isotherms, streamlines, average Nusselt number, and average temperature. It found that the Nu increases with a decrease in the number, height, and width of fins. Results showed that when the channel equipped with 16 fins the reduction in Nu value reaches 62% compared to the empty channel. In addition, at Ri = 1 and N = 8, the Nusselt number decreased by about 52-77% for different fin widths compared to the channel without fins. However, the Richardson number and inclination angle enhanced the heat transfer rate in terms of the average Nusselt number. It revealed that a higher heat transfer rate belongs to the Ri = 10 and φ = 60°. The finding of this work showed the capability of LBM in simulating the mixed convection heat transfer in an inclined channel equipped with fins. A numerical analysis of the results produced a comprehensive set of results that could be utilized to reduce heat transfer. This paper can provide a novel framework for the design of air solar collectors and heat exchange systems.

Numerical investigation of the effect of hot-water outlet inclination angle on the temperature dilution in open channel flow

In this study, the authors investigated the environmental impact of discharging hot water from a thermal power plant into a water source for cooling. Three hundred forty-three runs using two-dimensional numerical ANSYS Fluent simulation model with (k- ε) turbulence model and open channel flow characteristics was applied in this research. The single port submerged discharge inclination angle was studied with different scenarios for the hot-water outlet (velocity and temperature) to determine the optimum inclination angle to increase cooling system efficiency and reduce hot water's environmental impact. It was discovered that by increasing the inclination angle and velocity of the hot-water outlet, the efficiency of cooling system is increased, as it increased the dilution of the hot water and reduced its environmental impact. Specifically, inclination angle of 15° increased the dilution by 80% and 86% in x and y directions, respectively compared to angle 90°. Additionally, the temperature variation in water body induced by hot-water outlet was reduced by counter flow at angle −15°. The velocity profile showed a recirculation region at the right side of the hot-water outlet, which was reduced at higher inclinations. A mathematical equation was developed to estimate the temperature value in the open channel water body based on the study parameters. Overall, the study found that increasing the inclination angle of the hot-water outlet can significantly improve the cooling system's efficiency and reduce the environmental impact of the hot water discharge. Counter flow conditions were unsuitable because they have less dilution than the normal flow conditions.

Understanding of penetrating resistance on an inclined plate to cohesive soil using two-dimensional discrete element method

In order to know the effect of varied grousers on the reaction of soil, the reaction of soil by a plate at different angles of inclination using the two-dimensional discrete element method (DEM) has been investigated. Either the simulation or the experiment, a flat iron plate with 5 × 77 × 100 (mm) was used, and the inclination angle between the plate and the soil surface ranged from 0 to 60 degrees with 15-degree intervals. According to the result, the cohesive soil model introduced in the 2D DEM could successfully replicate the experimental results considering the effects of different inclination angles of the plate and the values of the root mean square error between the simulation and the experiment were found as 6.62, 36.60, 58.63, 60.84, and 66.25 N for inclination angles from 0 to 60 degrees in the horizontal direction. Moreover, the RMSE values of 127.91, 216.06, 75.88, 110.40, and 25.49 N were obtained for the vertical direction. Overall, a minimal discrepancy was observed between the results of DEM simulation and those of experiments in the vertical component of reaction force when the inclination angle of the plate was increased.

Experimental study on the effects of triangular groove inclination angles on the mechanical behavior of sand–concrete interfaces

The mechanical properties of pile–soil interfaces directly affect the bearing capacity of pile foundations. In this study, the effects of triangular groove inclination angles on the mechanical properties of sand–concrete interfaces were investigated. Random rough concrete surfaces were obtained through slurry intrusion testing, and the roughness of concrete surfaces was evaluated based on the sand cone method. According to the roughness of random concrete surfaces, five regular concrete surfaces with different triangular groove inclination angles were constructed. A series of direct shear tests between (i) sand and random concrete surface, (ii) sand and regular concrete surface, as well as (iii) sand and smooth concrete surface were performed. Moreover, a direct shear test of natural sand was conducted. Lastly, a shear strength model considering the triangular groove inclination angle of sand–concrete interfaces was established, and the shear failure mechanism of interfaces was discussed. The results firstly indicated that the shear stress-displacement curves of random rough concrete surfaces were ideal elastic-plastic curves; and the regular rough concrete surfaces were found to incur strain softening under a normal stress of 300 kPa. Secondly, the shear strength of sand–concrete interfaces increased with the increase in groove inclination angle of concrete interfaces. Thirdly, sand was found to achieve the highest shear strength, while sand–smooth concrete interfaces proved to attain the lowest. Lastly, the internal friction angle value of random concrete interfaces was shown to range between the values of concrete surfaces with triangular groove inclination angles of 70° and 90°.

Numerical study on cracking behavior and fracture failure mechanism of flawed rock materials under uniaxial compression

AbstractThe numerical approach is a vital means for evaluating the stability of flawed rocks. In this paper, the extended non‐ordinary state‐based peridynamics (NOSB‐PD) theory is employed to simulate the fracture process of rocks containing two pre‐existing flaws. Two stress criteria, including the maximum tensile stress criterion and the Mohr–Coulomb criterion, are implemented into the NOSB‐PD numerical method to respectively judge the tensile and shear failure of rock materials. The effects of inclination angles and ligament angles on the crack initiation and coalescence modes for flawed rocks are investigated based on the numerical results. The numerical results are in good agreement with the previous experimental results. The fracture mechanism of flawed rocks is revealed based on the evolutionary distribution characteristics of the maximum principal stress field and shear stress field obtained by the extended NOSB‐PD theory.

Concentration dependence of yield stress of bentonite suspension and corresponding particle interactions

The prediction of the concentration dependence of the yield stress of bentonite suspension is important for both practical use and fundamental study. Whilst a great amount of research work has been undertaken concerning the theoretical prediction based on the Face-Face repulsive interactions alone, the effect of inclination angle α and separation distance D between clay particles has seemingly received little attention in the research literature. This article presents the prediction model of yield stress developed using the strength of interparticle interactions between two non-parallel platy particles of finite dimensions, aimed at providing insights into the evolution of interparticle interaction with increasing the mass fraction. The repulsive force between the particles for a range of values of geometrical parameters computed using the Gouy-Chapman theory of electrical double layer, along with the calculation presented on van der Waals force, provide a more quantitative means of evaluating the interparticle force in bentonite suspension. It was found that as α and D between particles increase, the magnitude of interparticle force including repulsive and attractive force decreases quickly. The ultimate comprehensive investigation indicated that as the mass fraction of bentonite suspension increases, interparticle interaction propagates from attractive interaction to repulsive attraction, and finally shifts to attractive interaction. In this process, inter-particle separation distance decreases, accompanied by a transition process from a larger inclination angle to a nearly parallel orientation between the particles. The prediction model of yield stress considering the influence of concentration variation on α and D yields a good prediction of experimental data. The results of the present study should help interpret test results in cases where it may not be entirely possible to maintain a parallel particle orientation.

Assessment of the two-phase thermosyphon loop with high filling ratio under anti-gravity

In various fields of thermal management and protection, such as vehicles, aircraft, and mobile electronic devices, it is crucial to transfer heat effectively from the top to the bottom. The use of a simple structure for this transfer can reduce the weight of the heat transfer system. Theoretical studies have demonstrated that the two-phase thermosyphon loop (TPTL) with a high filling ratio has the potential for excellent performance in anti-gravity applications. In this study, we investigate the thermal performance of a high filling ratio TPTL under anti-gravity conditions. Our results reveal that, contrary to previous understanding, a TPTL with a high filling ratio can effectively transfer heat in anti-gravity. However, we also found that the loop thermal resistance of TPTL under anti-gravity is greater than under gravity, and the heating surface temperature is higher. Additionally, we experimentally study the effect of inclination angles on anti-gravity performance, and our results indicate that smaller angles result in better heat transfer. Finally, we investigate the impact of cooling water temperature on thermal performance. Overall, considering the energy efficiency of the heat dissipation system and the heat transfer capacity of the device, it is not recommended to use cooling water at a lower temperature. This research sheds light on the potential for TPTLs to operate in anti-gravity conditions and supports their practical applications.

Numerical study of the effect of heat-flow coupling on interface instability based on front tracking

The interfacial instability of two-phase immiscible fluids in inclined tubes at constant temperature boundary conditions is numerically investigated by the front-tracking method. By analyzing the effects of inclination angle φ, Marangoni number (Ma), and Rayleigh number (Ra) on the interfacial instability, the interaction law between unstable interface fluctuation and heat transfer is studied. The results show that the larger the inclination angle, the easier the interface is destabilized, and the heat transfer at the interface will also decrease. In the comparison of inclination angles of 0°, 30°, 45°, and 60°, the heat transfer is more stable at 45°. The heat flux between fluids decreases with the increase of Ma number, and Ma number has little effect on the interfacial fluctuation. It mainly affects the interfacial morphology by changing the surface tension gradient at the interface, which is mainly reflected in the end of the convolution interface. The larger the Ma number, the more inward the interface develops. Ra number has an obvious inhibitory effect on the interfacial instability. The effect of Ra number on heat-flow transfer at the interface shows alternating changes. In the initial stage, the heat transfer between fluids in the inclined tube is greater than that in the horizontal tube, but in the later stage, the heat transfer is less than that in the horizontal tube.