Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

2020 ◽  
Vol 1 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Mohammad Hatami ◽  
◽  
D Jing ◽  
Keyword(s):  
Heat Transfer ◽  
Least Square Method ◽  
Weissenberg Number ◽  
Least Square ◽  
Heat Transfer Analysis ◽  
Phase Method ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Nanoparticles Concentration ◽  
The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

scholarly journals Three-dimensional and two-phase nanofluid flow and heat transfer analysis over a stretching infinite solar plate

2018 ◽  
Vol 22 (2) ◽  
pp. 871-884 ◽  
Author(s):  
Mohammad Hatami ◽  
Mehdi Khazayinejad ◽  
Jiandong Zhou ◽  
Dengwei Jing
Keyword(s):  
Heat Transfer ◽  
Collocation Method ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Nanoparticles Concentration ◽  
Accuracy Of Results

In this work, 3-D and two-phase nanofluid flow and heat transfer is modeled over a stretching infinite solar plate. The governing equations are presented based on previous studies. The infinite boundary condition and shortcoming of traditional analytical collocation method have been overcome in our study by changing the problem into a finite boundary problem with a new analytical method called optimal collocation method. The accuracy of results is examined by fourth order Runge-Kutta numerical method. Effect of some parameters, Prandtl number, Schmidt number, Brownian motion parameter, thermophoresis parameter, ?=b/a (ratio of the stretching rate along y- to x-directions), and power-law index on the velocities, temperature, and nanoparticles concentration functions are discussed. As an important outcome of our 3-D model analysis, it is found that increase in thermophoretic forces can enhance the thickness of both thermal and nanoparticle volume fraction boundary-layers.

scholarly journals Experimental Investigation on Heat Transfer Mechanism of Air-Blast-Spray-Cooling System with a Two-Phase Ejector Loop for Aeronautical Application

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3963 ◽  
Author(s):  
Jia-Xin Li ◽  
Yun-Ze Li ◽  
Ben-Yuan Cai ◽  
En-Hui Li
Keyword(s):  
Heat Transfer ◽  
Droplet Size ◽  
Cooling System ◽  
Volumetric Flow Rate ◽  
Least Square Method ◽  
Spray Cooling ◽  
Cooling Capacity ◽  
Least Square ◽  
Two Phase ◽  
Air Blast

This paper presents an air-oriented spray cooling system (SCS) integrated with a two-phase ejector for the thermal management system. Considering its aeronautical application, the spray nozzle in the SCS is an air-blast one. Heat transfer performance (HTP) of air-water spray cooling was studied experimentally on the basis of the ground-based test. Factors including pressure difference between water-inlet-pressure (WIP) and spray cavity one (PDWIC) and the spray volumetric flow rate (SVFR) were investigated and discussed. Under a constant operating condition, the cooling capacity can be promoted by the growth factors of the PDWIC and SVFR with the values from 51.90 kPa to 235.35 kPa and 3.91 L ⋅ h − 1 to 14.53 L ⋅ h − 1 , respectively. Under the same heating power, HTP is proportional to the two dimensionless parameters Reynolds number and Weber number due to the growth of droplet-impacting velocity and droplet size as the increasing of PDWIC or SVFR. Additionally, compared with the factor of the droplet size, the HTP is more sensitive to the variation in the droplet-impacting velocity. Based on the experimental data, an empirical experimental correlation for the prediction of the dimensionless parameter Nusselt number in the non-boiling region with the relative error of only ± 10 % was obtained based on the least square method.

scholarly journals Heat transfer analysis of nanofluid flow through backward facing step

2020 ◽  
Vol 307 ◽  
pp. 01010 ◽  
Author(s):  
Ahlem Boudiaf ◽  
Fetta Danane ◽  
Youb Khaled Benkahla ◽  
Walid Berabou ◽  
Mahdi Benzema ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Thermal Characteristics ◽  
Heat Transfer Analysis ◽  
Backward Facing Step ◽  
Nanofluid Flow ◽  
Numerical Predictions ◽  
Flow Through ◽  
Volume Method

This paper presents the numerical predictions of hydrodynamic and thermal characteristics of nanofluid flow through backward facing step. The governing equations are solved through the finite volume method, as described by Patankar, by taking into account the associated boundary conditions. Empirical relations were used to give the effective dynamic viscosity and the thermal conductivity of the nanofluid. Effects of different key parameters such as Reynolds number, nanoparticle solid volume fraction and nanoparticle solid diameter on the heat transfer and fluid flow are investigated. The results are discussed in terms of the average Nusselt number and streamlines.

Numerical Simulation of Subcooled Flow Boiling Heat Transfer in Helical Tubes

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Jong Chull Jo ◽  
Woong Sik Kim ◽  
Chang-Yong Choi ◽  
Yong Kab Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steam Generator ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Heat Transfer Analysis ◽  
Normal Operation ◽  
Phase Flow ◽  
Two Phase ◽  
Side Flow

This paper addresses the numerical simulation of two-phase flow heat transfer in the helically coiled tubes of an integral type pressurized water reactor steam generator under normal operation using a computational fluid dynamics code. The shell-side flow field where a single-phase fluid flows in the downward direction is also calculated in conjunction with the tube-side two-phase flow characteristics. For the calculation of tube-side two-phase flow, the inhomogeneous two-fluid model is used. Both the Rensselaer Polytechnic Institute wall boiling model and the bulk boiling model are implemented for the numerical simulations of boiling-induced two-phase flow in a vertical straight pipe and channel, and the computed results are compared with the available measured data. The conjugate heat transfer analysis method is employed to calculate the conduction in the tube wall with finite thickness and the convections in the internal and external fluids simultaneously so as to match the fluid-wall-fluid interface conditions properly. Both the internal and external turbulent flows are simulated using the standard k-ε model. From the results of the present numerical simulation, it is shown that the bulk boiling model can be applied to the simulation of two-phase flow in the helically coiled steam generator tubes. In addition, the present simulation method is considered to be physically plausible in the light of discussions on the computed results.

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