Volume Fraction Of Al2O3 Nanoparticles Research Articles

Impacts of slip and activation energy on MHD hybrid nanofluid flow past a stretching radiated surface with heat generation/absorption

The influences of slip and activation energy on the magnetohydrodynamic (MHD) flow of hybrid nanofluid over a permeable stretching radiated surface in attendance of heat source/sink have been studied. Al2O3 and Cu nanoparticles are mixed up in water to produce a hybrid nanofluid which is very important in various industrial sectors as hybrid nanofluid has wider applications in enhancing thermal efficiency to provide efficient and reliable cooling. As no one has yet searched for the collective impacts of radiative heat flux, ‘heat generation/absorption’ and ‘Arrhenius activation energy’ on MHD flow of ‘hybrid nanofluid’ in presence of slip that we are exploring in this article, this identifies the novelty of our work. Using ‘similarity transformations’, the main equations which are partial in nature are transformed to ODEs (ordinary differential equations) which are numerically solved with the assistance of ‘shooting technique and Runge–Kutta method’ using MATHEMATICA software. The outcomes of this investigation have a noteworthy impact on the physical outlook for flow field, transfer of heat and mass. Fluid velocity diminishes due to the rise of magnetic parameter but increasing nature of concentration and temperature are observed. For the rising volume fraction of Al2O3 nanoparticles as well as for rising volume fraction of Cu nanoparticles, the heat transfer coefficient rises. Momentum ‘boundary layer thickness’ diminishes for rising velocity slip. 19.694% decrease in rate of surface heat transfer is observed when volume fraction of Al2O3 nanoparticles changes from 0.01 to 0.12 whereas 24.394% decrease is noted when volume fraction of Cu nanoparticles changes from 0.2 to 0.14. The consequences of this study can be applied to many thermal systems used in engineering and industrial developments that utilize hybrid nanofluid for heating and cooling purposes.

Computational Fluid Dynamics Analysis of Slip Flow and Heat Transfer at the Entrance Region of a Circular Pipe

In the era of sustainable development goals (SDGs), energy efficient heat transfer systems are a must. Convective heat transfer within circular pipes is an important field of research on a rarely addressed limitation of fluid flows. Vacuum solar tubes is one of many applications that could benefit from the existence of nanoparticles, Al2O3, for example, to enhance the heating of air or water steam. The current research investigates the impacts of the Reynolds number (Re), Prandtl number (Pr), Knudsen number (Kn), aspect ratio (x/Dh), and volume fraction of Al2O3 nanoparticles (ϕ) on the Nusselt number (Nu) under constant wall heat flux conditions. An axisymmetric computational fluid dynamics (CFD) analysis of the nanofluid flowing at the entrance region of a circular pipe was conducted under a slip flow at steady-state developing laminar conditions using the Ansys-Fluent 2018 software package. A mesh sensitivity analysis was conducted, and a proper number of mesh elements was selected. The results showed that an increasing Re and/or ϕ would result in an increasing Nu. The dependance of Nu on Kn was strong due to the high slip values and temperature jump. An increasing x/Dh ratio resulted in reduced Nu values. The major impact was due to Kn, which caused a reduction of up to 40% in the Nu value due to slip conditions. However, there was an enhancement of 2.5% in the heat transfer due to the addition of nanoparticles, which was found at Re = 250, Kn = 0.1, and ϕ = 0.1 (Pr = 0.729). Finally, Nuavg, Nux, U/Um, and ReCf were corelated with Kn, Pr, Re, and x/Dh with proper coefficient of determination (R2) values.

Analytical Investigation of Magnetohydrodynamic Hybrid Nanofluid Flow Over a Permeable Shrinking Sheet

The flow and heat transfer of Cu-Al2O3/water hybrid nanofluid over a shrinking sheet were investigated taking account of the magnetic field, suction, variable heat sink, and thermal radiation. At first, the governing equations were completely changed into ordinary differential equations (ODEs) with proper transformations. The novelty of this investigation is that the ODEs were analytically solved and the dual characteristics of flow properties and heat transfer were graphically presented. Results revealed that an increase in the volume fraction of Cu nanoparticles (φ2), magnetic parameter (M), and suction parameter (S) caused an increase in the local skin friction coefficient (Rex1/2Cf), local Nusselt number (Rex-1/2Nux) and region of the existence of dual solutions. With the increase of φ2, M, and S, fluid velocity increased and temperature decreased. Contrary to this, the converse was observed for increasing the volume fraction of Al2O3 nanoparticles (φ1). These findings indicated that with proper tuning of these parameters, the cooling rate of a shrinking sheet could be controlled and the possible working conditions of a system might be increased.

Effect of Al2O3 nanoparticles on microstructure and mechanical properties of friction stir-welded dissimilar aluminum alloys AA7075-T6 and AA6061-T6

In this research, a defect-free dissimilar weld joint of AA7075-T6 and AA6061-T6 reinforced with Al2O3 nanoparticles was fabricated via friction stir welding (FSW). The influence of tool rotational speed (700, 900 and 1100 rpm), traverse speed (40, 50 and 60 mm/min) with varying volume fractions of Al2O3 nanoparticles (4%, 7% and 10%) on microstructural evolution and mechanical properties were investigated. The augmentation of various mechanical properties is based on the homogeneity of particle dispersion and grains refinement in the SZ of the FSWed joint. The findings revealed that the remarkable reduction in grain size in the SZ was observed owing to the incorporation of Al2O3 nanoparticles produces the pinning effect, which prevents the growth of grain boundaries by dynamic recrystallization (DRX). The increasing volume fraction of Al2O3 nanoparticles enhanced the mechanical properties such as tensile strength, % elongation and micro-hardness. Agglomeration of particles was observed in the SZ of the FSWed joints produced at lower tool rotational speed of 700 rpm and higher traverse speed of 60 mm/min due to unusual material flow. Homogenous particle dispersion and enhanced material mixing ensue at higher rotational speed of 1100 rpm and lower traverse speed of 40 mm/min exhibit higher tensile strength and micro-hardness.

Experimental investigation on thermal properties of Al2O3 nanoparticles dispersed paraffin for thermal energy storage applications

ABSTRACT Addition of Al2O3 nanoparticles into paraffin wax is beneficial to improve the thermal conductivity of paraffin wax. Moreover, it has effect on the other thermophysical properties of paraffin wax such as the thermal diffusivity and volumetric heat capacity. In the present paper, the two-step method was used to prepare the nanofluids of Al2O3 nanoparticles and paraffin wax and then the influence of temperature and volume fraction of Al2O3 nanoparticles on the thermal conductivity, thermal diffusivity, and volumetric heat capacity of the nanofluids was investigated. The experimental results show that the changing trend of the above-mentioned properties of Al2O3/paraffin shows a slight regularity with increasing temperature. The thermal conductivity of nanofluids is enhanced at 20°C, and the largest thermal conductivity attained is 0.38 W/m·K at the volume fraction of 0.01%, which led to 40% augmentation, compared with paraffin. The thermal diffusivity of nanofluids with the volume fraction 0.01%, 0.1%, and 1% varies by −31%, 13.5%, and −21% in solid state, respectively. Moreover, the volumetric heat capacity fluctuates with the increase in temperature, and the volumetric heat capacity of nanofluids with the volume fraction 0.01% and 0.1% is higher than that of 1% in liquid state.

Numerical assessment on heat transfer performance of double-layered oblique fins micro-channel heat sink with Al2O3 nanofluid

This paper demonstrates a numerical study on heat transfer characteristics of laminar flow in a double-layered oblique finned heat sink using nanofluids with Al2O3 nanoparticles. Micro-channel heat sink with primary channel width of 0.5 mm with aspect ratio of 3 is employed. Instead of having conventional straight fins, oblique fins with narrow secondary channels are used. In this numerical study, single-phase fluid model with conjugate heat transfer is considered. The numerical modeling was first validated with existing data for double-layered conventional micro-channel heat sink having water (base fluid) as the working fluid. Numerical investigations on oblique finned micro-channel heat sink were then conducted for flow rates ranging from 3 ? 10?7 to 15 ? 10?7 m3/s, equivalent to primary channel inlet velocity in between 0.2 and 1.0 m/s. It was found that double-layered oblique finned configuration yields better heat transfer performance, inferred by the lower overall thermal resistance obtained as compared with that of double-layered conventional heat sink. Employing double-layered oblique finned heat sink, the heat transfer performance could be further enhanced, by using nanoparticles that are added into water-based fluid. It is found that the reduction of overall thermal resistance is proportional to the volume fraction of nanoparticles. Using cross-flow double-layered oblique finned configuration, the largest reduction in the overall thermal resistance can reach up to 25%, by using nanofluids with 4% volume fraction of Al2O3 nanoparticles.

Laminar Flow Forced Convective Heat Transfer Characteristics of Water-Based Al2O3 Nanofluids in a Horizontal Circular Tube with a Constant Heat Flux Boundary Condition

Transient two-dimensional numerical computations are carried out to clarify the laminar flow forced convective heat transfer characteristics of water-Al2O3 nanofluids in a horizontal circular tube with a constant heat flux boundary condition. The numerical results are presented over a wide range of diameters, volume fractions of Al2O3 nanoparticles, and Prandtl numbers. The ratio of average Nusselt numbers of water-Al2O3 nanofluids to that of water decreased with the increase of the volume fraction for three different diameters and Prandtl numbers. When the volume fraction is the same, the ratio of the average Nusselt numbers decreased as the diameter and Prandtl number decreases.

A coupled thermohydraulic/neutronic investigation of noise propagation in VVER-1000 reactor using[formula omitted] nanofluid coolant

Thermohydraulic and neutronic coupling for the VVER-1000 reactor carried out by applying Al2O3 nanofluid as coolant in this paper. The simulation took place in two sections; with the neutronic section, the discretization of the nodal (average current) method for dissociation of two-group diffusion equations accomplished and with the thermohydraulic section, the finite volume method for decomposition of conservation equations (mass, momentum and energy) in static and transient states was used.In this study, neutronic and thermohydraulic noises (Fourier transform) in the frequency domain were analyzed by applying propagation noise sources in the VVER-1000 reactor core. With the neutronic section, macroscopic cross sections were generated making use of Al2O3 nanofluid as coolant with different volume fractions by means of WIMS-D5 computation code.The ultimate goal of the paper is to perform neutronic and thermohydraulic simulations of VVER-1000 reactor using Al2O3 nanofluid as coolant in the frequency domain. Two separate noise scenarios for the inlet nanofluid coolant (coolant temperature and velocity) with different volume fractions of Al2O3 nanoparticles (0.001%, 0.1% and 1.0%) were considered in the analysis. Final results showed that the core power peaking factors will be less influenced by inlet fluctuations when applying more nanoparticles in the reactor coolant.

Thermal and hydrodynamic analysis of non-Newtonian nanofluid in wavy microchannel

In this study, hydrodynamic and heat transfer of non-Newtonian nanofluid behavior is investigated in a wavy microchannel with rectangular obstacles. Aluminum oxide as nanoparticles (Al2O3) with 0.5% and 1.5% volume fractions and three different diameters (25, 45 and 100 nm) are added to pure water as a base phase to form a nanofluid structure. In order to form the non-Newtonian nanofluid, 0.5% carboxy methyl cellulose (CMC) is added to the nanofluid structure. Up and down walls of microchannels at the middle section where obstacles are located have constant 50,000 W⁄m2 heat flux. Inlet temperature is constant and equal to 298 K with different Reynolds numbers varying as 5, 50, 150 and 300. Rib heights varying between 3 and 7 μm for five cases with different nanoparticle volume fractions, nanoparticle diameters and Reynolds numbers are investigated. Nusselt number, friction factor and pressure drop are studied. Results indicated that the average Nusselt number is increased by increasing the volume fraction of Al2O3 nanoparticles. Also, the results show the largest friction factor value is obtained in the case with the highest obstacle height. It is observed that MC-3 case has maximum outlet temperature, and therefore is the best case among investigated cases.

Processing parameters optimization to produce nanocomposite using friction stir welding

This paper deals with the fabrication of particulate metal-matrix nanocomposites (PMNCs) reinforced with Al2O3 nanoparticles via friction stir welding (FSW) process. The reinforcement particles (RPs) are incorporated inside the base matrix on abutting edges under different FSW process parameters to achieve maximum joint efficiency. The effect of different parameters namely tool rotational speed, transverse speed, and volume fraction of Al2O3 nanoparticles as input parameters on the ultimate tensile strength (UTS) of the produced nanocomposites has been investigated using the Taguchi methodology. Analysis of variance was employed to obtain the significance of independent variables on overall quality characteristics of friction stir welded nanocomposites. The multi-response optimized variables were found as: tool rotational speed = 2000rpm, transverse speed = 70 mm min−1 and volume fraction of Al2O3 nanoparticles = 0.30%. Based on the optimized parameters, the maximum ultimate tensile strength of the produced PMNCs was 218 MPa. The optimum results obtained using Taguchi method has been validated by conducting confirmation experiments. Macro and microstructural characterization of the produced nanocomposites using scanning electron microscopes revealed that the increase in the amount of heat due to tool stirring action as well as the addition of Al2O3 nanoparticles in the nugget zone leads to improve the interfacial bonding between the reinforcement particles and the base metal matrix and in turn produce the fine PMNCs.

Computational modeling of porous medium inside a channel with homogeneous nanofluid

In the present study, the flow field and heat transfer have been simulated numerically inside a channel. The channel is under the constant heat flux. The main objective of this research is investigating the effect of the arrangement of the porous medium in water/Al2O3 nanofluid inside the channel on the flow and heat transfer characteristics. The effect of various arrangements of porous medium with two porosities and different volume fractions of nanoparticles has been investigated in a constant cross section of the porous medium. The results are validated with other references, and excellent consistency has been seen. The results show that using the porous medium has more effect on heat transfer than using nanofluid, and the arrangement of the porous medium has a strong influence on temperature profile and heat transfer. Based on the results, using stair arrangement of porous medium with the distance of 30 cm from each other and the length of 30 cm and using nanofluid with 0.02 volume fraction of Al2O3 nanoparticles have better performance than other considered arrangements.

Al2O3-Water Nanofluids for Heat Transfer Application

AbstractThis manuscript aims at synthesizing Al2O3-de-ionized water nanofluid and constructing a practical design of self-cooling device that does not require any external power input. Crystalline phase of powder was confirmed by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) showed the various functional groups and absorption bands and average particle size was calculated to be 58.608 nm by Field Emission Scanning Electron Microscopy (FESEM) annealed at 900K. Experimental investigations were carried out to determine the effect of volume fraction of Al2O3 nanoparticles in the nanofluid on the rate of heat transfer from heat load to heat sink. Temperature of heat load was taken as 80° C. According to our results, cooling by 15°C, 13°C and 12°C was attained when volume fraction of nanoparticles was 1.5%, 1% and 0.5% respectively. The thermal conductivity was also measured and found to be increasing with the concentration of nanoparticles in nanofluid. Hence, indicating the use of nanofluids with suitable concentration in various cooling applications.

Three-Dimensional Numerical Study on Thermal-Hydraulic Performance of Twisted Mini-Channel Using Al2O3-H2O Nanofluid

Effects of design parameters of the twisted mini-channel, including twist pitch, width, height, and length, are investigated numerically at the Reynolds numbers between 300 and 1500. The Al2O3-H2O nanofluid is used as working fluid, and it is simulated using the mixture two-phase model. The volume fraction of Al2O3 nanoparticles is 1, 2, 3, and 4%. The results show that decreasing of twist pitch and channel length leads to higher values of the Nusselt number. As the Reynolds number is increased, the influence of these factors enhances. The increase of the channel width and height decreases the convective thermal resistance and thus improves the Nusselt number along with a certain penalty in the pressure drops. For all models, by increasing the volume fraction of nanoparticles, the convective thermal resistance is reduced leading to the thermal performance improvement. Finally, two correlations are proposed for the Nusselt number and friction factor, which are useful as a tool to predict the heat transfer and pressure drop characteristics of the twisted mini-channel.

On the heat transfer effects of nanofluids within rotor-stator cavities

Owing to the rapid development of a number of technological and industrial sectors, high-performance electronic devices are now ubiquitous in modern engineering and industrial applications. Effective heat management is crucial to the smooth operation of such devices, and sometimes conventional methods of heat transfer fail to deliver the required performance. Recent advances in the field of nanofluids are a promising route to improve heat-transfer performance, and this is our motivation. We propose two computational fluid dynamics models for a rotor-stator cavity operating at Reω = 1.0 × 105 and filled with a fluid that consists of different volume fractions of Al2O3 nanoparticles. The first model simulates the nanofluid mixture using a single-phase transport model, and the second approach uses a two-phase transport model that allows for the relative velocity between the particle and fluid phases. All simulations are conducted using the second-order accurate solver, OpenFOAM®, that is based on the finite volume method and using Large eddy simulation methods. Our results show that the higher volume fractions of Al2O3 nanoparticles can achieve higher heat transfer rates, and at the same time, dilute nanoparticle concentrations have subtle effects on the momentum transport of the system. This is an advantage over micro-particle dispersion. Furthermore, we consider the effects of particle forces in the two-phase model, such as Brownian and thermophoresis forces, and suggest that the thermophoresis forces are the dominant effect within the cavity geometry.

Investigating the effects of geometric parameters on finned conical helical geothermal heat exchanger and its energy extraction capability

With the onset of the warm and cold season, the temperature inside the building goes far away from the human comfort condition, so an optimal energy source is needed to reach the desired temperature. Naturally, the earth is a massive source of heat that is easily accessible under the buildings, yards, and squares of the city; therefore, the geothermal heat exchangers can be used in depth of the ground to drain the heat from the earth. In optimizing heat transfer equipment to achieve higher energy efficiency, the focus is on reducing the size of the heat exchanger on the one hand and increasing the intensity of heat transfer area on the other hand. Helical heat exchangers are compact and can be used in geothermal systems to receive energy. In this paper, a conical coil tube geothermal heat exchanger is simulated according to the environmental conditions of Tehran, the capital city of Iran, and the potential of using such system is examined by changing the geometric parameters and operational requirements. The coil diameter, coil pitch and the angle of conic of the helical tube are varied for the heat exchanger buried at a depth of 3m from the earth surface. The soil temperature profile is obtained from the air temperature data Synoptic Meteorological Station. Design parameters are coil diameter, coil pitch, cone angle, length to width ratio of the fin, number of fins and Reynolds number. Taguchi algorithm is applied to find the best geometric parameters. Finally, different volume fractions of Al2O3 nanoparticles are added to the optimized geometry to enhance the heat transfer rate. Results indicate that the optimized geometry considering thermal-hydraulic performance in the range of this study is θ=0°, Dc=1000 mm, Pc=60 mm, Re=3000, R=1 and Fn=6 for cone angle, coil diameter, coil pitch, Reynolds number, length to width ratio of fin and number of fins respectively. Changing the objective to increase heat transfer (Nusselt number) the optimized values alter to θ=3.14°, Dc=1000 mm,Pc=80 mm, Re=4993, R=1.5 and Fn=6. Heat flux on the surface of the tube increases to 18% for 0.5% volume fraction of nanoparticles.

Microstructure, Mechanical Properties and Wear Behavior of the Rheoformed 2024 Aluminum Matrix Composite Component Reinforced by Al2O3 Nanoparticles

The 2024 nanocomposite reinforced with Al2O3 nanoparticles was fabricated by the ultrasonic assisted semisolid stirring (UASS) method and rheoformed into a cylinder component. Microstructure, mechanical properties, and wear behavior of the rheoformed composite components were investigated. The results showed that the composite components with complete filling status and a good surface were rheoformed successfully. The deformation of semisolid slurries was mainly dominated by flow of liquid incorporating solid grains (FLS), sliding between solid grains (SSG), and plastic deformation of solid grains (PDS). Mechanical properties of the rheoformed composite components were influenced by stirring temperature, stirring time, and volume fraction of Al2O3 nanoparticles. The optimal ultimate tensile strength (UTS) of 358 MPa and YS of 245 MPa were obtained at the bottom of the rheoformed composite components after a 25-min stirring of composite semisolid slurry with 5% Al2O3 nanoparticles at 620 °C. Enhancement of mechanical properties was attributed to high density dislocations and dislocation tangles and uniform dispersed Al2O3 nanoparticles in the aluminum matrix. Natural ageing led to the occurrence of needle-like Al2CuMg phase and short-rod-like Al2Cu phase. UTS of 417 MPa and YS of 328 MPa of the rheoformed composite components were achieved after T6 heat treatment. Improvement of mechanical properties is due to the more precipitated needle-like Al2CuMg phase and short-rod-like Al2Cu phase. Wear resistance of the rheoformed composite components was higher than that of the rheoformed matrix component. Wear resistance of the rheoformed composite component increased with an increase in Al2O3 nanoparticles from 1% to 7%. A slight decrease in wear rate resulted from 10% Al2O3 nanoparticles due to greater agglomeration of Al2O3 nanoparticles. A combination mechanism of adhesion and delamination was determined according to worn surface morphology.

Numerical investigation on Al2O3/water nanofluid flow through twisted-serpentine tube with empirical validation

Laminar flow and heat transfer of Al2O3/water nanofluid in the twisted-serpentine tube (TST) are investigated numerically. The numerical results are validated with data obtained from the empirical part of the study. The influences of three specific design factors, including serpentine pitch (sp = 0.01, 0.02, and 0.03 m), straight length (sl = 0.05, 0.010, and 0.15 m), and twisted pitch (tp = 0.025, 0.050, and 0.075 m), are tested and discussed. The obtained results show that the straight length has the highest impacts on the performance of TST, followed by the twisted pitch and the serpentine pitch. It is also found that the Nusselt number of TST enhances as the volume fraction of Al2O3 nanoparticles increases. However, the effect of volume fraction on the friction factor is not noticeable. The overall analysis shows when a twisted-straight tube is bended and changed to the TST, its hydrothermal performance factor enhances by a factor between 1.74 and 2.77. It is detected that the performance factor can be enhanced up to 3.73 when the Al2O3/water nanofluid is applied as working fluid. Finally, correlations are developed for the TST, which fit the obtained results with the mean absolute error of 2.3% for the Nusselt number and 1.9% for the friction factor.

Characterization of Al2O3-SAE 15W40 engine oil nanolubricant and performance evaluation in 4-stroke diesel engine

This work aims to characterize Al2O3-SAE 15W40 engine oil nanolubricant and its performance evaluation in 4-stroke diesel engine. Field emission scanning electron microscope (FESEM) images of nanoparticle reveal the spherical morphology of nanoparticle and Fourier transform infrared spectroscopic results show chemical stability of nanolubricants. Dynamic light scattering test display the presence of mild agglomeration of particles in nanolubricants, further FESEM images of dispersed nanoparticles re-confirms it. Density and viscosity of nanolubricants are measured with varying particle volume fraction and temperature. The overall performance of nanolubricant is tested on a 4-stroke diesel engine. The nanolubricant with 0.3% volume fraction of Al2O3 nanoparticles shows less frictional power loss and hence higher brake thermal efficiency as compared to other nanolubricants.

Numerical study of turbulent nanofluid heat transfer in a tubular heat exchanger with twin twisted-tape inserts

In the present study, the turbulent flow of water/Al2O3 nanofluid in a tubular heat exchanger with two twisted-tape inserts has been numerically investigated in the three-dimensional coordinate. This numerical simulation has been done by using FVM, and all of the equations have been discretized by second-order upwind method. For coupling velocity–pressure equations, SIMPLEC algorithm has been used. The investigated parameters of the present study are Reynolds numbers at the range of 10,000–30,000, the effect of twist ratio of twisted-tape inserts from 2.5 to 4, co-swirl flow and counter-swirl flow of two twisted-tapes inside the tube and volume fractions of nanofluid from 1 to 4%. The results of this research revealed that, by decreasing the twist ratio, the counter-swirl flow twisted-tape and the enhancement of volume fraction of Al2O3 nanoparticles in the base fluid, the amount of average Nusselt number increases. In twist ratios of 3.25 and 2.5, the maximum amounts of performance evaluation criterion (PEC) are 1.6 and 1.55, respectively. Also, the amount of PEC improvement in counter-swirl flow state is considerably more than co-swirl flow state. Therefore, the maximum enhancements of PEC improvement in three twist ratios of 4, 3.25 and 2.5 are, respectively, 40.8, 47 and 51% and the maximum enhancements in three mentioned ratios are 26.5, 28.3 and 30.6%, respectively.

The numerical investigation of heat transfer and pressure drop of turbulent flow in a triangular microchannel

In this presentation, the flow and heat transfer inside a microchannel with a triangular section, have been numerically simulated. In this three-dimensional simulation, the flow has been considered turbulent. In order to increase the heat transfer of the channel walls, the semi-truncated and semi-attached ribs have been placed inside the channel and the effect of forms and numbers of ribs has been studied. In this research, the base fluid is Water and the effect of volume fraction of Al2O3 nanoparticles on the amount of heat transfer and physics of flow have been investigated. The presented results are including of the distribution of Nusselt number in the channel, friction coefficient and Performance Evaluation Criterion of each different arrangement. The results indicate that, the ribs affect the physics of flow and their influence is absolutely related to Reynolds number of flow. Also, the investigation of the used semi-truncated and semi-attached ribs in Reynolds number indicates that, although heat transfer increases, but more pressure drop arises. Therefore, in this method, in order to improve the heat transfer from the walls of microchannel on the constant heat flux, using the pump is demanded.