Irregular Heat Research Articles

Impact of Lorentz Force on Unsteady Bio Convective Flow of Carreau Fluid across a Variable Thickness Sheet with Non-Fourier Heat Flux Model

In this article, we examined the magnetohydrodynamic Cattaneo-Christov bio convective flow of Carreau liquid over a variable thickness sheet with irregular heat sink/source. The fluid motion is supposed to be time dependent and not turbulent. Firstly, proper transmutations are pondered to metamorphose the basic flow equations as ODE. The solution of these ODEs is procured by the sequential execution of R.K. and Shooting numerical treatments. The density of motile organisms, concentration, temperature and velocity distributions for dissimilar values of non-dimensional parameters are perused via graphs. Further, we analyzed the impact of same parameters on friction factor, local Nusselt number and the rate of mass transfer coefficients and presented in table. Results indicate that the distribution of the density of motile organisms is an increasing function of Peclet and Lewis numbers. Fluid velocity is proportional to the Weissenberg number. Also the space dependent heat sink/source parameters perform obligatory role in the mass and heat transport performance.

Nonlinear radiated MHD flow of nanoliquids due to a rotating disk with irregular heat source and heat flux condition

This research is made to visualize the nonlinear radiated flow of hydromagnetic nano-fluid induced due to rotation of the disk. The considered nano-fluid is a mixture of water and Ti6Al4V or AA7072 nano-particles. The various shapes of nanoparticles like lamina, column, sphere, tetrahedron and hexahedron are chosen in the analysis. The irregular heat source and nonlinear radiative terms are accounted in the law of energy. We used the heat flux condition instead of constant surface temperature condition. Heat flux condition is more relativistic and according to physical nature of the problem. The problem is made dimensionless with the help of suitable similarity constraints. The Runge-Kutta-Fehlberg scheme is adopted to find the numerical solutions of governing nonlinear ordinary differential systems. The solutions are plotted by considering the various values of emerging physical constraints. The effects of various shapes of nanoparticles are drawn and discussed.

Comment on the paper “Marangoni convective MHD flow of SWCNT and MWCNT nanoliquids due to a disk with solar radiation and irregular heat source, B. Mahanthesh, B. J. Gireesha, N.S. Shashikumar, S.A. Shehzad, Physica E 94 (2017) 25–30”

The present comment concerns some doubtful results included in the above paper.

Effect of Thermophoresis and Brownian Moment on 2D MHD Nanofluid Flow over an Elongated Sheet

In this study, we investigated the 2D MHD flow of a dissipative Maxwell nanofluid past an elongated sheet with uneven heat source/sink, Brownian moment and thermophoresis effects. The flow governing PDEs are transmuted into nonlinear ODEs adopting the suitable similarity transmissions. Further, the RK-4 technique is employed to acquire the numerical solutions. The impact of pertinent parameters such as thermal radiation, frictional heating, irregular heat source/sink, biot number, Brownian moment and thermophoresis on the flow quantities such as velocity, thermal and concentration fields likewise friction factor, heat and mass transfer rates are bestowed with the succour of graphs and tables. Dual nature is witnessed for Newtonian and non-Newtonian fluid cases. It is noticed that the heat and mass transfer rate in Newtonian fluid larger as compared with non-Newtonian fluid.

Marangoni convective MHD flow of SWCNT and MWCNT nanoliquids due to a disk with solar radiation and irregular heat source

Present study addresses the Marangoni transport of dissipating SWCNT and MWCNT nanofluids under the influence of magnetic force and radiation. A novel exponential space dependent heat source is considered. The flow is generated due to a disk with surface tension created by thermal gradient. The partial differential equations system governing the flow of carbon-water nanoliquids and heat transfer through Marangoni convection is established. Subsequent system is reduced to nonlinear ordinary boundary value problem via generalized Karman transformations. Numerical solutions are developed of the arising nonlinear problem via Runge-Kutta based shooting approach. Impacts of embedded parameters are focused on Nusselt number, velocity and heat transport distributions through graphical illustrations. Our simulations figured out that the heat transfer rate increased via Marangoni convection; however it is decayed by applied magnetic force. The temperature of SWCNT-H2O nanoliquid dominates MWCNT-H2O nanoliquid.

Effect of cross diffusion on MHD non-Newtonian fluids flow past a stretching sheet with non-uniform heat source/sink: A comparative study

The present study sought to report the combined influences of frictional and irregular heat on MHD non-Newtonian fluid (Casson and Maxwell) flows due to stretched surface. The action of thermal diffusion and diffusion thermo is scrutinized. The flow will take place due to stretched surface. The equations determining the flow condition are transfigured as coupled equations through self similarity transmutations. R.K. Fehlberg technique is implemented to acquire the solution of the problem. Graphs are plotted to inspect the influence of sundry physical quantities on the three routine profiles of the flow field. Further, expressions are procured for friction factor along with the rate of heat and mass transfers and discussed comprehensively through tabular forms. Results indicate that Casson fluid attains highest velocity when compared with Maxwell fluid. The mass transfer rate in Maxwell fluid is better than that of Casson fluid whereas a dissimilar phenomenon is discerned in heat transfer rate. Also Eckert number and irregular heat parameters have tendency to exalt the fluid temperature.

Combined influence of viscous dissipation and non-uniform heat source/sink on MHD non-Newtonian fluid flow with Cattaneo-Christov heat flux

This paper is perpetrated to inspect the MHD flow and heat transfer of two distinct non-Newtonian fluids across a stretching sheet with the new heat flux theory namely Cattaneo-Christov. Using this model, one can discern the impact of thermal relaxation time. Casson and viscoelastic fluids are supposed for the present perusal. The impacts of frictional heat and irregular heat are accounted. According to the heat variations in the nature or in any other system, the radiation effect on the flows may be linear or nonlinear. So the current investigation is aimed at nonlinear radiation. The flow governing equations have been altered as ODE via appropriate transmutations and then resolved by adopting R-K and Newton calculations. Graphs are displayed to discern the influence of physical parameters entered into the problem. The shear stress and heat transfer coefficients are also tabulated. It is inferred that Casson fluid obtains better velocity compared with viscoelastic fluid. Also, it is essential to disclose that thermal relaxation time exhibits dual behaviour on Casson fluid temperature. Also there is intensification in thermal boundary layer thickness with the enlargement of temperature ratio or frictional heat.

Hall effect on two-phase radiated flow of magneto-dusty-nanoliquid with irregular heat generation/consumption

Abstract Impacts of Hall current and irregular heat generation/consumption on two-phase flow of dusty-nanofluid are scrutinized. Particulate nanofluid saturates the stretched surface. Heat transfer mechanism is studied via radiative heating and viscous dissipation aspects. The nanoliquid is a carrier fluid and dust (micro-sized fine particles) particles are suspended in it. Governed equations are remodeled in the form of ordinary differential system using stretching transformations. Numeric solutions are developed via Runge-Kutta-Fehlberg scheme. The influence of pertinent parameters on both nanofluid and particle phase flow fields are studied through graphs. The friction factor and Nusselt number are also studied. It is established that the Hall current has a significant impact on thermal flow fields. The irregular heat generation/consumption aspect is constructive for the heating process.

Effect of Temperature Dependent Viscosity on MHD Radiative Nanofluid Flow Caused by Heated/Cooled Cone

In this study, we investigated the temperature dependent viscosity effect on magnetohydrodynamic nanofluid flow caused by a heated/cooled cone in the presence of nonlinear thermal radiation and irregular heat source/sink. The transformed governing equations using similarity variables are solved numerically using Runge-Kutta based shooting technique. We demonstrated solutions for Al2O3-water and TiO2-water nanofluid cases. The effects of various dimensionless parameters on velocity and temperature profiles along with the skin friction coefficient and the local Nusselt number are discussed and presented with the help of graphs and tables. It is found that the viscous variation parameter help to control the velocity as well as the temperature field and regulates the friction factor and heat transfer rate.

Extension and anterior alignment of the prosthetic foot normalizes hip and knee loading symmetry in unilateral trans-tibial amputees

Lower limb prosthetic alignment is a procedure mostly subjective. A prosthetic misaligned induces gait deviations and long-term joint diseases. The alignment effects for each lower limb and the stump stays uncertain.To identify the effect of the transfemoral alignment prosthesis on ground reaction forces and thermal images of the residual limb.The effect of misalignment and nominal alignment was evaluated in sixteen transfemoral amputees. The nominal alignment was considered as the optimal alignment for each subject. Misalignment included random variations in the anterior-posterior and medial-lateral translation of the prosthetic foot and the angle of flexion-extension, abduction-adduction, and internal-external rotation of the socket and prosthetic foot. The control group consisted of fifteen non-amputee individuals. The ground reaction force parameters and stump temperature were analyzed for each alignment condition. The statistical analysis included the one-way ANOVA, Kruskal-Wallis, and multiple comparison tests.The prosthesis did not produce statistically significant changes in the average temperature of residual limbs. However, the temperature distribution on the stump skin was different (P < 0.05). The transfemoral prosthesis misalignment produced an irregular heat diffusion on the anterior, posterior, and lateral sides of the stump contour compared to the nominal alignment (P < 0.05). The sound limb did not show differences between nominal alignments and misalignments for most ground reaction force parameters. For almost all GRF parameters, significant differences were observed for the prosthetic limb between misalignment and nominal alignment (P < 0.001). The symmetry indices of ground reaction force parameters of transfemoral amputees did not show any kind of significant improvements after aligning the prosthesis nominally.The stump's temperature distribution and the ground reaction force findings for the prosthetic limb provide a better understanding of the alignment procedure of the transfemoral prosthesis and improve the amputees' compliance to the prosthesis.

РЕЗУЛЬТАТЫ ИСПЫТАНИЯ СЕЛЕКЦИОННОГО МАТЕРИАЛА ОВСА В ТАЕЖНОЙ ЗОНЕ ЗАПАДНОЙ СИБИРИ

The studies found out that the productivity and quality of oat crop accessions were influenced by the climatic conditions during the vegetation period and plant mineral nutrition level. Under favorable weather and soil conditions the accessions demonstrated a reliable yield increase (0.35-0.37-0.40 t/ha), increased weight of 1000 grains and lesser grain husk. With irregular heat and humidity on poor naturally fertile soils, the growing season of mid-ripening varieties was longer, while for mid-early ones becamer shorter; grain yield was lower than in dry environments.

Numerical investigation of the energy performance of a guideless irregular heat and mass exchanger with corrugated heat transfer surface for dew point cooling

The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy efficiency (i.e. Coefficient of Performance (COP)) of the air cooling process. CFD simulation was carried out to determine the flow resistance (K) factors of various elements within the dry and wet channels of the exchanger, while the ‘finite-element’ based ‘Newton-iteration’ numerical simulation was undertaken to investigate its cooling capacity, cooling effectiveness and COP at various geometrical and operational conditions. Compared to the existing flat-plate heat and mass exchangers with the same geometrical dimensions and operational conditions, the new irregular exchanger could achieve 32.9%–37% higher cooling capacity, dew-point and wet-bulb effectiveness, 29.7%–33.3% higher COP, and 55.8%–56.2% lower pressure drop. While undertaking dew point air cooling, the irregular heat and mass exchanger had the optimum air velocity of 1 m/s within the flow channels and working-to-intake air ratio of 0.3, which allowed the highest cooling capacity and COP to be achieved. In terms of the exchanger dimensions, the optimum height of the channel was 5 mm while its length was in the range 1–2 m. Overall, the proposed irregular heat and mass exchanger could lead to significant enhanced energy performance compared to the existing flat-plate dew point cooling heat exchanger of the same geometrical dimensions. To achieve the same amount cooling output, the irregular heat and mass exchanger had the reduced size and cost against the flat-plate ones.

The Numerical Simulation Research on Heat Exchanging Enhancement and Structural Optimization of the Flue Gas Heat Transfer of Mixed Arrangement Irregular Heat-Pipe

The mixed arrangement irregular heat-pipe flue gas heat transfer was researched, using numerical simulation method. The irregular heat-pipe: triangle heat pipe; square heat pipe. The heat pipe equivalent diameter of flue gas heat transfer is 20 mm, the speed of inlet flue gas is 11 m/s, the inlet temperature of flue gas is 500 K. the results show mixed arrangement irregular heat-pipe can enhance heat exchanging, the optimal parameters of mixed arrangement structure in the condition of given working condition: the first row is triangle heat pipe, the second row is circular heat pipe, the third row is triangle heat pipe, row 4 is square heat pipe, the line spacing of the first row and second is 40 mm, the line spacing of the second and third row is 40 mm, the line spacing of the third row and the fourth row is 35 mm, and the row spacing of the tube is 40 mm. the heat transfer efficiency of the optimized irregular heat-pipe-exchanger raised 40 ~ 60%.

Molecular dynamical simulations of the melting properties of Aln(n=13–32) clusters

Based on the Gupta-type semi-empirical inter-atomic many body potential, the melting properties of Aln(n=13–32) clusters are systematically investigated by using the molecular dynamics method combined with the simulated annealing and quenching techniques. Our results show that, except for several sizes (Al13 and Al19), in general the heat capacity curves all are in disorder (no obvious single-peak), which are consistent with the experimental observations that small aluminum clusters have messy heat capacity curves in the melting process. Reasons for the different melting behaviors (whether they exhibit regular or irregular heat capacity curves) of these small Al clusters can be explored by analyzing the energy distributions of the simulated quenching structures of these clusters at different temperatures. For the clusters with disordered heat capacity curves one can obtain the melting points from analyzing the atomic equivalence indexes of those clusters, and the variations of the calculated melting points of the aluminum clusters with increasing cluster size are in agreement with the experimental observations.

Active surface of the elements of irregular heat and mass transfer packings

The mechanisms of active surface formation in irregular heat and mass transfer packings were analyzed. The packings under study included Raschig, Pall, and GIAP-N3 rings and Intallox saddles. The efficiencies of GIAP-N3 packings of different sizes under different gas and liquid loads were compared. The packing designs were compared in terms of the useful factor of packing.

Active surface of elements of irregular heat and mass transfer packing

The mechanisms of active surface formation in irregular heat and mass transfer packings were analyzed. The packings under study included Raschig, Pall, and GIAP-N3 rings and Intallox saddles. The efficiencies of GIAP-N3 packings of different sizes under different gas and liquid loads were compared. The packing designs were compared in terms of the useful factor of packing.

Influence of the diameter of perforation holes on operating indices of irregular heat and mass transfer packing

The influence of the diameter of perforation holes on the operation main indices of irregular metal heat and mass transfer packing is considered.

An effect of sprinkling density on a value of active surface of irregular heat and mass transfer packing

The results of analysis of an influence of a sprinkling density in the packed columns were reported on a value of an active surface of irregular ring nozzles such as Raschig and Pall rings. Sizes of Raschig rings were 15, 25 and 50 mm; Pall rings, 50 mm. Values of fluid load was 10, 20, 30, 40 and 50 m3 m−2 h−1). The results of the analysis were presented in graph form.

변위센서를 이용한 적응적 PID제어기반 자동차 변속기 샤프트 교정시스템

In this paper, we proposed a new shaft distortion correction system having an adaptive PID controller using displacement sensors, which is adaptively reflecting variations of shaft strength owing to irregular heat treatment during an annealing process and sensitivity to the seasonal temperature changes. Generally, the shafts are annealed by heat treatment in order to enlarge the strength of the shaft, which causes an distortion of a shaft such as irregular bending of the shaft. In order to correct such a distortion of the shaft, a mechanical pressure is properly impacted to the distorted shaft. However, the strength of every shaft is different from each other owing to irregular annealing and seasonal temperature changes. Especially, the strength of a thin shaft such as a car transmission shaft is much more sensitive than that of a thick shaft. Therefore, it is very important for considering the strength of each shaft during correction of the car transmission shaft distortion in order to generate proper mechanical pressure. The conventional PID controller for the shaft distortion correction system does not consider each different strength of each shaft, which causes low productivity. Therefore, we proposed a new PID controller considering variations of shaft strength caused by seasonal temperature changes as well as irregular heat treatment and different cooling time. Three displacement sensors are used to measure a degree of distortion of the shaft at three different location. The proposed PID controller generates adaptively different coefficients according to different strength of each shaft using appropriately obtained pressure times from long-term experiments. Consequently, the proposed shaft distortion correction system increases the productivity about 30 % more than the conventional correction system in the real factory.

Irregular Heat Flow Problems

We study a nonsteady transmission problem across either a fractal layer S or the corresponding prefractal layer $S_h$. The transmission condition is of order two. Existence, uniqueness, and regularity results for the strict solution, in both cases, are established as well as convergence results for the solutions of the approximating problems in varying Hilbert spaces.