Impact of Smoluchowski Temperature and Maxwell Velocity Slip Conditions on Axisymmetric Rotated Flow of Hybrid Nanofluid past a Porous Moving Rotating Disk

Colloidal suspensions of regular fluids and nanoparticles are known as nanofluids. They have a variety of applications in the medical field, including cell separation, drug targeting, destruction of tumor tissue, and so on. On the other hand, the dispersion of multiple nanoparticles into a regular fluid is referred to as a hybrid nanofluid. It has a variety of innovative applications such as microfluidics, heat dissipation, dynamic sealing, damping, and so on. Because of these numerous applications of nanofluids in minds, therefore, the objective of the current exploration divulged the axisymmetric radiative flow and heat transfer induced by hybrid nanofluid impinging on a porous stretchable/shrinkable rotating disc. In addition, the impact of Smoluchowski temperature and Maxwell velocity slip boundary conditions are also invoked. The hybrid nanofluid was formed by mixing the copper (Cu) and alumina (Al2O3) nanoparticles scattered in the regular (viscous) base fluid (H2O). Similarity variables are used to procure the similarity equations, and the numerical outcomes are achieved using bvp4c in MATLAB software. According to the findings, double solutions are feasible for stretching (λ>0) and shrinking cases (λ<0). The heat transfer rate is accelerated as the hybrid nanoparticles increases. The suction parameter enhances the friction factors as well as heat transfer rate. Moreover, the friction factor in the radial direction and heat transfer enrich for the first solution and moderate for the second outcome due to the augmentation δ1, while the trend of the friction factor in the radial direction is changed only in the case of stretching for both branches.

Manipulating the interlayer carrier diffusion and extraction process in organic-inorganic heterojunctions: from 2D to 3D structures

Interlayer carrier transfer at heterointerfaces plays a critical role in light to electricity conversion using organic and nanostructured materials. However, how interlayer carrier extraction at these interfaces is poorly understood, especially in organic-inorganic heterogeneous systems. Here, we provide a direct strategy for manipulating the interlayer carrier diffusion process, transfer rate and extraction efficiency in tetracene/MoS2 type-II band alignment heterostructure by constructing the 2D–3D organic-inorganic (O-I) system. As a result, the prolonged diffusion length (12.32 nm), enhanced electron transfer rate (9.53 × 109 s−1) and improved carrier extraction efficiency (60.9%) are obtained in the 2D O-I structure which may be due to the more sufficient charge transfer (CT) state generation. In addition, we have demonstrated that the interlayer carrier transfer behavior complied with the diffusion mechanism based on the one-dimensional diffusion model. The diffusion coefficients have varied from 0.0027 to 0.0036 cm2 s−1 as the organic layer changes from 3D to 2D structures. Apart from the relationship between the carrier injection and diffusion process, temperature-dependent time-resolved spectra measurement is used to reveal the trap-related recombination that may limit the interlayer carrier extraction. The controllable interlayer carrier transfer behavior enables O-I heterojunction to be optimized for optoelectronic applications.

Analysis of Thermal Performances in a Ventilated Room Using LBM-MRT: Effect of a Porous Separation

This article demonstrates the feasibility of porous separation on the performance of displacement ventilation in a rectangular enclosure. A jet of fresh air enters the cavity through an opening at the bottom of the left wall and exits through an opening at the top of the right wall. The porous separation is placed in the center of the cavity and its height varies between 0.2 and 0.8 with three values of thickness, 0.1, 0.2, and 0.3. The heat transfer rate was calculated for different intervals of Darcy (10−6 ≤ Da ≤ 10), Rayleigh (10 ≤ Ra ≤ 106), and Reynolds (50 ≤ Re ≤ 500) numbers. The momentum and the energy equations were solved by the lattice Boltzmann method with multiple relaxation times (LB-MRT). Schemes D2Q9 and D2Q5 were chosen for the velocity and temperature fields, respectively. For porous separation, the generalized Darcy–Brinkman–Forchheimer model was adopted. It is represented by a term added in the standard LB equations. For the dynamic domain, numerical simulations revealed complex flow structures depending on all control parameters. The results showed that the thermal field, mainly in the second compartment, is very dependent on the size and permeability of the porous separation. However, they have no influence on the transfer rate.

Impacts of Joule heating and viscous dissipation on MHD pulsatile flow of third grade nanofluid in a channel

The current exploration deals with the third grade hydromagnetic pulsating flow of blood-gold nanofluid in a channel with the presence of Ohmic heating, viscous dissipation and radiative heat. In the present analysis, blood (base fluid) is considered as third-grade fluid and gold (Au) as nanoparticle. This investigation is useful in the fields of food processing system, pressure surges (pulsatile flow application), biomedical engineering, nano drug delivery, radiotherapy, and cancer therapeutic (nanofluid application). Perturbation method is employed to transform the set of governing partial differential equations (PDEs) into the ordinary differential equations (ODEs) and then solved by employing the fourth order Runge-Kutta method with the aid of the shooting technique. The impacts of emerging dimensionless parameters of velocity, temperature, and heat transfer rate of blood-Au nanofluid are analysed via pictorial outcomes in detail. The obtained results depict that the improvement in viscous dissipation and heat source enhanced the temperature of third grade nanofluid. The velocity and temperature of the nanofluid are declining functions with the enhancement of frequency parameter, material parameter, and non-Newtonian parameter respectively. Intensifying the volume fraction of nanoparticle dwindles the velocity and temperature of nanofluid. Enhancing volume fraction and viscous dissipation accelerates the heat transfer rate of nanofluid. The velocity, temperature, and heat transfer rates are decreased by an escalation of the Hartmann number. Further, enhancing the radiation parameter reduces the heat transfer rate and temperature of nanofluid.

Heat Transfer Enhancement by Perforated and Louvred Fin Heat Exchangers

Multi-tube multi-fin heat exchangers are extensively used in various industries. In the current work, detailed experimental investigations were carried out to establish the flow/heat transfer characteristics in three distinct heat exchanger geometries. A novel perforated plain fin design was developed, and its performance was evaluated against standard plain and louvred fins designs. Experimental setups were designed, and the tests were carefully carried out which enabled quantification of the heat transfer and pressure drop characteristics. In the experiments the average velocity of air was varied in the range of 0.7 m/s to 4 m/s corresponding to Reynolds numbers of 600 to 2650. The water side flow rates in the tubes were kept at 0.12, 0.18, 0.24, 0.3, and 0.36 m3/h corresponding to Reynolds numbers between 6000 and 30,000. It was found that the louvred fins produced the highest heat transfer rate due to the availability of higher surface area, but it also produced the highest pressure drops. Conversely, while the new perforated design produced a slightly higher pressure drop than the plain fin design, it gave a higher value of heat transfer rate than the plain fin especially at the lower liquid flow rates. Specifically, the louvred fin gave consistently high pressure drops, up to 3 to 4 times more than the plain and perforated models at 4 m/s air flow, however, the heat transfer enhancement was only about 11% and 13% over the perforated and plain fin models, respectively. The mean heat transfer rate and pressure drops were used to calculate the Colburn and Fanning friction factors. Two novel semiempirical relationships were derived for the heat exchanger’s Fanning and Colburn factors as functions of the non-dimensional fin surface area and the Reynolds number. It was demonstrated that the Colburn and Fanning factors were predicted by the new correlations to within ±15% of the experiments.

Vibrational Data Communication Tools and Methods for Mining and Oil and Gas Extraction

Summary For the purpose of exploration and extraction, the drilling process in the mining and oil and gas industries is very complicated because of the obvious invisibility of the operation of the drill bit. Acoustic/vibrational telemetry has been of keen interest because it is so far the only method that allows a high data transfer rate as well as less data loss, over other methods. The method certainly depends on the use of the right communication tools and efficient communication schemes to achieve the highest data transfer rate. Although the acoustic method provides a very high data transmission rate, it also has its limitations. However, limitations can be overcome through certain approaches and the use of technologies. The proper use of a communication device with the steel pipe is the most important factor to consider so that the transducer works as the right actuator for the pipeline. The type of sensor that is used to pick up the data also plays a major role because signals are most likely to attenuate, and a sensitive sensor is necessary to collect these attenuated signals. This research demonstrates the use of a transducer as a communication device and oil and gas pipe as the medium of data transmission. The transducer can be used both as an actuator driver and as a receiver sensor. A new piezoelectric transducer was manufactured for this research, which was used with a test setup of a total 184 ft length of six oil and gas pipes. The test setup performed well and data were sent through this setup successfully. A communication scheme is developed using novel theories to achieve the highest data transfer rate. The scheme is tested with the transfer function data obtained from the experimental system. The communication scheme developed outputs a signal, which is a type of binary phase-shift keying signal data along with an equalizer filter. Then the signals developed from the scheme are used in the actual experimental setup to test the speed of the transmission and bit error rate (BER). For the six oil and gas pipes setup, the scheme provides a data transmission of 153 bits/sec (bps) with zero error percentage, which is high enough to use in any oil and gas industry.

Numerical investigations of heat transfer around a hot block subject to a cross-flow and an extended jet hole using ternary hybrid nanofluids

In the last few years, modern heat transfer technologies significantly improved to provide more efficient systems in industries. One of those technologies is cooling electronic components in laminar flow using water nanofluids, which is interesting. This research used a ternary hybrid nanofluid with various nanoparticle forms to conduct a numerical investigation of three-dimensional heat transfer and fluid flow over a heated block exposed to a horizontal flow and an impinging jet. The effects of several variables such as the Reynolds number ratio [Formula: see text], volume fraction of nanoparticles [Formula: see text], length of extended jet hole [Formula: see text], and the influence of the inclination angle of the impinging jet inlet [Formula: see text] on the fluid flow and heat transfer were examined. Using the Ansys-Fluent 14.5 program and under laminar flow conditions, the finite-volume method was applied with the help of the SIMPLE algorithm to solve continuity, momentum, and energy equations. Several characteristics are assessed, including velocity streamline, isotherm contours, Nusselt number contours, the average Nusselt number ([Formula: see text]), the friction factor [Formula: see text], and drop pressure [Formula: see text]. The findings of the current analysis revealed that adding an impinging jet can boost the heat transfer rate up to [Formula: see text] better than a non-impingement jet. Also, a significant enhancement in the heat transfer rate was obtained when growing one of these parameters α, [Formula: see text], and E. Moreover, the ternary hybrid nanofluid with different nanoparticle forms significantly boosts the heat transfer rate compared to the traditional nanofluid. The maximum heat transfer is reached as the velocity of the impinging jet rises. Inclining the angle of the impinging jet inlet with [Formula: see text] toward the channel inlet boosted the rate of heat transfer up to [Formula: see text] compared to the perpendicular impinging jet [Formula: see text]. A strong consensus has been reached with the theoretical and experimental findings found in the literature.

Transient Fluid-Solid Interaction and Heat Transfer in a Cavity with Elastic Baffles Mounted on the Sidewalls

Fluid-solid interaction phenomenon study is necessary for the analysis of several engineering systems such as structures and vessels that interact with wind and blood flow, respectively. In this study, the interactions between buoyancy-driven airflow and elastic baffle(s) inside a square enclosure were modeled numerically. While the two sidewalls of the enclosure were insulated, the lower and upper walls were kept at hot and cold temperatures, respectively. The heat transfer rate through the hot wall by calculating the Nusselt number and von Mises stress at the baffles’ root for various configurations of baffle(s) was considered. The domain was modeled in ANSYS Workbench, and the k-ε model was employed to solve the turbulent convective flow (Ra > 107). A two-way algorithm along with the finite element method was employed to simultaneously solve the equations governing the fluid flow and the solid phase. The dynamic mesh method was employed to account for the change in the location of the fluid domain at a new time step. The results show the elastic baffle, in comparison to solid baffle, intensifies the heat transfer rate by 15%. The results also indicate that the Nusselt number in the single-baffle case is higher than in double-baffle cases. The fact that the amount of von Mises is a function of the baffles’ configuration is another point obtained from the results. It was found that the von Mises stress at the baffles’ root represents more unsteady fluctuations in the asymmetric case, while it approaches a constant value in the symmetric case.

Effect of Fin Number and Position on Non-linear Characteristics of Natural Convection Heat Transfer in Internally Finned Horizontal Annulus

Detailed numerical calculations are performed for investigating the effect of fin number and position on unsteady natural convection heat transfer in internally finned horizontal annulus. The SIMPLER algorithm with Quick scheme is applied for solving the Navier Stokes equations of flow and heat transfer. The results show that the heat transfer rate in annulus with fins increases with the increasing numbers of fin and Rayleigh numbers. For Ra = 2 × 105, the effect of numbers of fins and fins position at the bottom part on the unsteady solutions can be neglected, because the self-oscillation phenomenon is mainly affected by natural convection at the upper part of annulus. Although the fin positions cannot increase heat transfer rate significantly in the case of four fins, the self-oscillated solutions can be suppressed by altering fins position.