Trapezoidal Microchannels Research Articles

Retraction notice: Investigation of laminar fluid flow and heat transfer of nanofluid in trapezoidal microchannel with different aspect ratios

Retraction notice: Investigation of laminar fluid flow and heat transfer of nanofluid in trapezoidal microchannel with different aspect ratios

Assessment of Vapor Formation Rate and Phase Shift between Pressure Gradient and Liquid Velocity in Flat Mini Heat Pipes as a Function of Internal Structure.

Flat mini heat pipes (FMHPs) are often used in cooling systems for various power electronic components, as they rapidly dissipate high heat flux densities. The main objective of the present work is to experimentally investigate whether differences in the rate of vapor formation occur on an internal structure containing trapezoidal microchannels and porous sintered copper powder material. Several parameters, such as hydraulic diameter and fluid velocity through the material, as a function of the internal structure porosity, were determined by calculation for a steady state regime. Reynolds number was determined as a function of porosity, according to Darcy's law, and the Nusselt number was calculated. Since the flow is Darcy-type through the porous medium inside the FMHP, the Darcy friction factor was calculated using five methods: Colebrook, Darcy-Weisbach, Swamee-Jain, Blasius, and Haaland. After experimental tests, it was found that when the porous and trapezoidal microchannel layers are wetted at the same time, the vaporization progresses at a faster rate in the porous material, and the duration of the process is shorter. This recommends the use of such an internal structure in FMHPs since the manufacturing technology is simpler, the materials are cheaper, and the heat flux transport capacity is higher.

The Effect of Geometric Parameters on Flow and Heat Transfer Characteristics of a Double-Layer Microchannel Heat Sink for High-Power Diode Laser.

The effect of the geometric parameters on the flow and heat transfer characteristics of a double-layer U-shape microchannel heat sink (DL-MCHS) for a high-power diode laser was investigated in this work. FLUENT 19.2 based on the finite volume method was employed to analyze the flow and heat transfer performance of DL-MCHS. A single variable approach was used to fully research the impact of different parameters (the number of channels, the channel cross-sectional shape, and the aspect ratio) on the temperature distribution, pressure drop, and thermal resistance of the DL-MCHS. The rectangular DL-MCHS heat transfer performance and pressure drop significantly increased with the rise in the channel's aspect ratio due to there being a larger wet perimeter and convective heat transfer area. By comparing the thermal resistance of the DL-MCHS at the same power consumption, it was found that the rectangular DL-MCHS with an aspect ratio in the range of 5.1180-6.389 had the best overall performance. With the same cross-sectional area and hydraulic diameter (AC = 0.36 mm, Dh = 0.417 mm), the thermal resistance of the trapezoidal microchannel heat sink was 32.14% and 42.42% lower than that of the triangular and rectangular ones, respectively, under the condition that the pumping power (Wpp) was 0.2 W. Additionally, the thermal resistance was reduced with the increment of the number of channels inside the DL-MCHS, but this would induce an increased pressure drop. Thus, the channel number has an optimal range, which is between 50 and 80 for the heat sinks in this study. Our study served as a simulation foundation for the semiconductor laser double-layer U-shaped MCHS optimization method using geometric parameters.

Parametric study and optimization of microchannel heat sinks with various shapes

In this study, laminar single-phase fluid flow and conjugate heat transfer for three different shapes of microchannel heat sinks (MCHS) were numerically investigated using Computational Fluid Dynamics (CFD) and optimized with Non-dominated Sorting Genetic Algorithm II (NSGA-II) to reveal geometric design variables for optimum solutions. A clear comparison of different shapes of MCHS under the same design constraints is necessary to establish an understanding of efficient MCHS designs. The hydraulic diameters of rectangular, triangular and trapezoidal microchannels were kept constant at 150 μ m for a fair comparison. Minimization of power consumption and enhancing heat transfer were determined as objective functions of the optimization represented by pumping power and averaged Nusselt number (Nu). The objective functions were expressed in terms of the design variables consisting of Reynolds number (Re), aspect ratio of rectangular channel, apex angle of triangular channel and junction angle of trapezoidal channel. For each configuration, parametric CFD analyzes were performed to establish correlations between design variables and objective functions to be used in the optimization process. For the rectangular MCHS configuration, low aspect ratio was shown to increase heat transfer with a power consumption penalty. For triangular and trapezoidal microchannels, 50° of apex angle and 60° of junction angle were suggested as optimum geometric parameters, respectively. Pareto frontal comparison of the three configurations revealed that rectangular microchannel was the most effective configuration in terms of thermal and hydrodynamic performance. For the same amount of heat transfer, the rectangular microchannel configuration required 17% and 40% less pumping power than the trapezoidal and triangular microchannels, respectively. • Conjugate heat transfer is numerically investigated for MCHS. • Parametric analyzes are performed for three different MCHS configurations. • Nusselt number and pumping power are the objective functions. • Hydrodynamic and thermal performance are compared for various channel shapes. • Optimization is integrated to the solutions to better understand the problem.

Effect of Cross-Sectional Geometry on Hydrothermal Behavior of Microchannel Heat Sink

Abstract The aim of this paper is to numerically analyze the hydrothermal behavior of different cross-sectional geometries of microchannel heat sinks (MCHSs) and conduct a comparative analysis of traditional and non-traditional designs using ANSYS Fluent. It is expected that the proposed design discussed in this paper will improve the performance of MCHSs by maximizing the cooling capability and minimizing the thermal resistance and entropy generation rate, thus leading to better energy efficiency. The channel designs include a rectangular microchannel (RMC), a circular microchannel (CMC), an elliptical microchannel (EMC), a trapezoidal microchannel (TMC), a hexagonal microchannel (HMC), and a new microchannel (NMC) which has a plus-like shape. The discussed geometry of the NMC is designed in such a way that it maximizes the cross-sectional area and the wetted perimeter of the channel, keeping the hydraulic diameter constant ( D h = 412 {D_{h}}=412 µm). The performance of various channels is compared on the basis of pressure drop, wall temperature, thermal enhancement factor, thermal resistance, thermal transport efficiency, and entropy generation rates. It has been observed that the NMC is capable of cooling effectively and it can achieve a minimum wall temperature of 305 K, thus offering the lowest thermal resistance ( R th {R_{\mathrm{th}}} ), irreversible heat loss, and entropy generation rate. Moreover, the NMC has achieved the highest value of the thermal enhancement factor, i. e., 1.13, at Re = 1 , 000 \mathrm{Re}=1,000 . Similarly, it has the highest thermal transport efficiency of almost 97 % at Re = 1 , 000 \mathrm{Re}=1,000 , followed by the TMC and the RMC. Overall, the NMC has achieved the best performance in all aspects, followed by the RMC and TMC. The performance of the EMC, the CMC, and the HMC was found to be the worst in this study.

Flow and Heat Transfer in a Trapezoidal Cross-Sectional Microchannel Heat Sink Using Nanofluid

In this study, the effects of microchannel number, volume concentration, Reynolds number, and nanofluid type on heat transfer and flow characteristics in the heat sink consisting of trapezoidal microchannels are investigated numerically. Governing equations are solved by assuming three-dimensional, incompressible, steady and laminar flow. The channel material is chosen as copper, and a constant heat flux boundary condition is defined on the upper wall of heat sink. For two different nanofluids, CuO-water and Al2O3-water, investigated parameters are the number of trapezoidal channels (n=3-5) in the heat sink, Reynolds number (Re=200-1500), and volume concentration (=0-4%). Results show that using nanoparticles in base fluid causes to increase both heat transfer coefficient and pressure drop. Heat transfer coefficient increases with increasing number of trapezoidal cross-sectional channel in the heat sink, nanofluid volume concentration and Reynolds number. Pressure drop enhances with enhancing Reynolds number and microchannel number in the heat sink. The nanofluid type and volume concentration do not importantly affect the friction factor. According to the performance index, it is seen that adding CuO nanoparticles in water is convenient, but Al2O3 nanoparticles in water is not appropriate. It is observed that volume concentration for CuO-water nanofluid affects the thermal performance, but volume concentration for Al2O3-water nanofluid does not affect.

Effect of transverse and parallel magnetic fields on thermal and thermo-hydraulic performances of ferro-nanofluid flow in trapezoidal microchannel heat sink

Purpose This paper aims to study the thermal and thermo-hydraulic performances of ferro-nanofluid flow in a three-dimensional trapezoidal microchannel heat sink (TMCHS) under uniform heat flux and magnetic fields. Design/methodology/approach To investigate the effect of direction of Lorentz force the magnetic field has been applied: transversely in the x direction (Case I);transversely in the y direction (Case II); and parallel in the z direction (Case III). The three-dimensional governing equations with the associated boundary conditions for ferro-nanofluid flow and heat transfer have been solved by using an element-based finite volume method. The coupled algorithm has been used to solve the velocity and pressure fields. The convergence is reached when the accuracy of solutions attains 10–6 for the continuity and momentum equations and 10–9 for the energy equation. Findings According to thermal indicators the Case III has the best performance, but according to performance evaluation criterion (PEC) the Case II is the best. The simulation results show by increasing the Hartmann number from 0 to 12, there is an increase for PEC between 845.01% and 2997.39%, for thermal resistance between 155.91% and 262.35% and ratio of the maximum electronic chip temperature difference to heat flux between 155.16% and 289.59%. Also, the best thermo-hydraulic performance occurs at Hartmann number of 12, pressure drop of 10 kPa and volume fraction of 2%. Research limitations/implications The embedded electronic chip on the base plate generates heat flux of 60 kW/m2. Simulations have been performed for ferro-nanofluid with volume fractions of 1%, 2% and 3%, pressure drops of 10, 20 and 30 kPa and Hartmann numbers of 0, 3, 6, 9 and 12. Practical implications The authors obtained interesting results, which can be used as a design tool for magnetohydrodynamics micro pumps, microelectronic devices, micro heat exchanger and micro scale cooling systems. Originality/value Review of the literature indicated that there has been no study on the effects of magnetic field on thermal and thermo-hydraulic performances of ferro-nanofluid flow in a TMCHS, so far. In this three dimensional study, flow of ferro-nanofluid through a trapezoidal heat sink with five trapezoidal microchannels has been considered. In all of previous studies, in which the effect of magnetic field has been investigated, the magnetic field has been applied only in one direction. So as another innovation of the present research, the effect of applying magnetic field direction (transverse and parallel) on thermo-hydraulic behavior of TMCHS is investigated.

Heat Transfer Analysis of Flat Heat Pipe With Enhanced Microchannel Shape

Flat heat pipe has many excellent characteristics such as high thermal conductivity, reversibility of heat flow direction and so on. In this paper, a flat heat pipe model with multiple microchannels is established, and the effects of different microchannel shapes and different materials on the heat transfer efficiency of flat heat pipe are studied. Then, based on the general rectangular and inverted trapezoidal microchannel shape, the enhancement is carried out. That is to fill a number of materials in the bottom of the microchannel to change the bottom shape of the microchannel. In the steady-state thermal simulation of flat heat pipe, the axial temperature of the flat heat pipe with enhanced microchannel shape is lower than that of the flat heat pipe with general microchannel, which shows that the enhanced microchannel shape is helpful to the heat dissipation of flat heat pipe. The fluid simulation results show that the enhanced rectangular microchannel shape can accelerate the flow velocity of working fluid. Therefore, the flat heat pipe with enhanced microchannel shape has better heat transfer performance. In order to obtain the local temperature of flat heat pipe quickly, the transient analytical solution is provided. In this paper, the temperature field calculated by using transient analytical solution is compared with that simulated by COMSOL. The results show that the maximum error between the results of discrete heat source model and continuous heat source model calculated by transient solution and COMSOL simulation results is less than 2%.

Numerical studies on the hydraulic and thermal performances of trapezoidal microchannel heat sink

The present work numerically studies the hydraulic and thermal performances of trapezoidal microchannel heat sink (TMCHS) with rectangular cross-sectional shape under the constant total channel volume. Considering the flow direction, channel arrangement direction and inlet location, TMCHSs with six different configurations are proposed to compare their hydraulic and thermal performances. The results demonstrate that the pressure drop of the six THCHSs always increases with the decreasing small-to-large end width ratio. For the thermal performance, only the two TMCHSs with Parallel Channel Parallel Flow Large Inlet (PCPFLI) and Reverse Channel Counter Flow Large Inlet (RCCFLI) configurations have improved thermal performances with the decreasing small-to-large end width ratio, including decreasing maximum temperature, decreasing thermal resistance and decreasing center zone temperature difference. On the basis of these, the effects of the channel height and inlet flowrate on the thermal performances of TMCHSs with PCPFLI and PCPFLI configurations are further studied. It is found that PCPFLI and RCCFLI configurations have lower thermal resistance and more uniform temperature distribution with increasing channel height and inlet flowrate. The TMCHS with RCCFLI configuration has the best thermal performances among the six TMCHSs. The findings reported in present work provide a simple method to improve the thermal performances of MCHS by changing the channel shape and configurations.

Motion of an Elastic Capsule in a Trapezoidal Microchannel Under Stokes Flow Conditions.

Even though the research interest in the last decades has been mainly focused on the capsule dynamics in cylindrical or rectangular ducts, channels with asymmetric cross-sections may also be desirable especially for capsule migration and sorting. Therefore, in the present study we investigate computationally the motion of an elastic spherical capsule in an isosceles trapezoidal microchannel at low and moderate flow rates under the Stokes regime. The steady-state capsule location is quite close to the location where the single-phase velocity of the surrounding fluid is maximized. Owing to the asymmetry of the trapezoidal channel, the capsule’s steady-state shape is asymmetric while its membrane slowly tank-treads. In addition, our investigation reveals that tall trapezoidal channels with low base ratios produce significant off-center migration for large capsules compared to that for smaller capsules for a given channel length. Thus, we propose a microdevice for the sorting of artificial and physiological capsules based on their size, by utilizing tall trapezoidal microchannels with low base ratios. The proposed sorting microdevice can be readily produced via glass fabrication or as a microfluidic device via micromilling, while the required flow conditions do not cause membrane rupture.

Numerical Analysis of a Trapezoidal Microchannel for Hydrodynamic Detachment of Cells

Hydrodynamic shear force along the bottom microchannel wall has been utilized in cell adhesion studies to detach cells in microfluidic channels. Due to the small dimensions of microfluidic channels, the shear stress produced in a conventional microchannel is dependent mainly on the fluid velocity and channel height. The wall shear force magnitude increases as the channel height is reduced. However, a reduced channel height decreases the sample volume to be contained in the fluidic channel and also increases the pressure drop significantly which may fail the fluidic device. In this study, a novel microchannel with a trapezoidal structure was investigated using computational fluid dynamics simulations. The key fluidic properties, including wall shear stress, sample volume, and pressure drop of the trapezoidal microchannel are compared with those of a conventional straight channel with a reduced channel height. We found the trapezoidal structure produces a wall shear stress of 5 Pa in the region of interest similar to that of the straight channel with a small channel height (50 μm) while having less than 30 percent pressure drop. Additionally, the pressure drop can be reduced by modifying the geometry of the trapezoidal channel to minimize pressure loss.

Hydrothermal performance analysis of various surface roughness configurations in trapezoidal microchannels at slip flow regime

Abstract The effects of various surface roughness geometrical properties including roughness height (5%, 10%, 15%), number (3, 6), and shape (rectangular and triangular) on the flow and heat transfer of slip-flow in trapezoidal microchannels were investigated. The effects of mentioned parameters on the heat transfer coefficient through the microchannel, average Nusselt number and pressure drop for Reynolds number of 5, 10, 15 and 20 were examined. The obtained results showed that increasing the roughness height and number increases the pressure drop due to higher stagnation effects before and after roughness elements and decreases the Nusselt number due to higher recirculation zones effects than obstruction effects. The most reduction in Nusselt number and the most increment in pressure drop occur at the roughness height of 15%, roughness number of 6 and Reynolds number of 20 by about 10.6% and 52.8% than the smooth microchannel respectively.

3D Printing of Inertial Microfluidic Devices

Inertial microfluidics has been broadly investigated, resulting in the development of various applications, mainly for particle or cell separation. Lateral migrations of these particles within a microchannel strictly depend on the channel design and its cross-section. Nonetheless, the fabrication of these microchannels is a continuous challenging issue for the microfluidic community, where the most studied channel cross-sections are limited to only rectangular and more recently trapezoidal microchannels. As a result, a huge amount of potential remains intact for other geometries with cross-sections difficult to fabricate with standard microfabrication techniques. In this study, by leveraging on benefits of additive manufacturing, we have proposed a new method for the fabrication of inertial microfluidic devices. In our proposed workflow, parts are first printed via a high-resolution DLP/SLA 3D printer and then bonded to a transparent PMMA sheet using a double-coated pressure-sensitive adhesive tape. Using this method, we have fabricated and tested a plethora of existing inertial microfluidic devices, whether in a single or multiplexed manner, such as straight, spiral, serpentine, curvilinear, and contraction-expansion arrays. Our characterizations using both particles and cells revealed that the produced chips could withstand a pressure up to 150 psi with minimum interference of the tape to the total functionality of the device and viability of cells. As a showcase of the versatility of our method, we have proposed a new spiral microchannel with right-angled triangular cross-section which is technically impossible to fabricate using the standard lithography. We are of the opinion that the method proposed in this study will open the door for more complex geometries with the bespoke passive internal flow. Furthermore, the proposed fabrication workflow can be adopted at the production level, enabling large-scale manufacturing of inertial microfluidic devices.

Numerical analysis on thermal performance of a trapezoidal micro-channel heat sink using an improved version of the augmented ε-constraint method

This work proposes the use of an improved version of the augmented ε-constraint method (AUGMENCON2) for the analysis of the thermal performance of a micro-channel heat sink. In order to highlight the strength and the effectiveness of this new approach, a trapezoidal micro-channel heat sink has been considered. The geometrical configuration namely the micro-channel widths and depth are the main variables considered in this study. Surrogate models based on the response surface methodology have been adopted to approximate the thermal resistance and the pumping power which provide an indication of the thermal performance of the micro-channel heat sink. A two-objective nonlinear problem have been formulated and implemented within the general algebraic modelling system. Global Pareto optimal solutions have been computed using the proposed method. Despite being a relatively straightforward method, the AUGMENCON2 provides a reasonable level of accuracy and shortens the required computational time in comparison to two existing approaches.

Numerical analysis on thermal performance of a trapezoidal micro-channel heat sink using an improved version of the augmented ε-constraint method

This work proposes the use of an improved version of the augmented e-constraint method (AUGMENCON2) for the analysis of the thermal performance of a micro-channel heat sink. In order to highlight the strength and the effectiveness of this new approach, a trapezoidal micro-channel heat sink has been considered. The geometrical configuration namely the micro-channel widths and depth are the main variables considered in this study. Surrogate models based on the response surface methodology have been adopted to approximate the thermal resistance and the pumping power which provide an indication of the thermal performance of the micro-channel heat sink. A two-objective nonlinear problem have been formulated and implemented within the general algebraic modelling system. Global Pareto optimal solutions have been computed using the proposed method. Despite being a relatively straightforward method, the AUGMENCON2 provides a reasonable level of accuracy and shortens the required computational time in comparison to two existing approaches.

Empirical correlation of laminar forced convective flow in trapezoidal microchannel based on experimental and 3D numerical study

In this paper, the fluid flow and heat transfer characterizations in trapezoid shaped microchannel with H1 (axially constant heat flux and circumferentially constant temperature) and H2 (constant axial and circumferential wall heat flux) boundary conditions are studied. A three-dimensional numerical model is developed for trapezoidal geometries with side-angles of 30° and 60° with different aspect ratios ranging from 0.1 to 10 to evaluate the Nusselt number and Poiseuille number for fully-developed and developing flow conditions. Experiments are performed on a trapezoidal microchannel and experimental results are compared with the three-dimensional conjugate heat transfer numerical model. It is found that the experimental results are close to the H1 boundary condition. The Nusselt number and Poiseuille number are found to be increasing with the side-angle and aspect ratio of trapezoidal channel. Generalized correlations for Poiseuille number, Nusselt number and entrance length are developed for trapezoidal channel with side angles in the range of 30°–60° and aspect ratios of 0.1–10. These correlations can be used for designing of trapezoidal microchannel in future heat transfer applications.

Fabrication of trapezoidal cross-sectional microchannels on PMMA with a multi-pass translational method by CO2 laser

CO2 lasers with a wavelength of 10.6 μm are often used to produce PMMA microchannels, as non-metallic materials have a strong absorption capability at this wavelength. Generally, triangular cross-section microchannels have been fabricated by conventional laser ablation method due to the Gaussian distribution of laser intensity. In many cases, the traditional method cannot meet the requirements of the microfluidic chips’ manufacture. In this paper, a multi-pass translational method is introduced. The method based on the lateral heat-affected zone (HAZ) formed by single ablation and multiple ablation with its width as the translation distance. The multi-pass translational method not only produces a clean bottom like the static multi-pass method but can modify the cross-sectional topography to produce a clean trapezoidal microchannel. In this research, the topography of microchannel is evaluated by introducing a new parameter "S", the variations in surface roughness and HAZ. Furthermore, the width and the depth of microchannels via laser translational writing are studied by analytical modeling. The experimental results confirmed that the multi-pass translational method is a quick and economical way of fabricating high quality trapezoidal microchannel on PMMA for microfluidic devices application.

Numerical Study of Double-Layered Microchannel Heat Sinks with Different Cross-Sectional Shapes.

This work numerically studies the thermal and hydraulic performance of double-layered microchannel heat sinks (DL-MCHS) for their application in the cooling of high heat flux microelectronic devices. The superiority of double-layered microchannel heat sinks was assessed by a comparison with a single-layered microchannel heat sink (SL-MCHS) with the same triangular microchannels. Five DL-MCHSs with different cross-sectional shapes—triangular, rectangular, trapezoidal, circular and reentrant Ω-shaped—were explored and compared. The results showed that DL-MCHS decreased wall temperatures and thermal resistance considerably, induced much more uniform wall temperature distribution, and reduced the pressure drop and pumping power in comparison with SL-MCHS. The DL-MCHS with trapezoidal microchannels performed the worst with regard to thermal resistance, pressure drop, and pumping power. The DL-MCHS with rectangular microchannels produced the best overall thermal performance and seemed to be the optimum when thermal performance was the prime concern. Nevertheless, the DL-MCHS with reentrant Ω-shaped microchannels should be selected when pumping power consumption was the most important consideration.

Investigation of laminar fluid flow and heat transfer of nanofluid in trapezoidal microchannel with different aspect ratios

PurposeIn the present study, laminar steady flow of nanofluid through a trapezoidal channel is studied by using of finite volume method. The main aim of this paper is to study the effect of changes in geometric parameters, including internal and external dimensions on the behavior of heat transfer and fluid flow. For each parameter, an optimum ratio will be presented.Design/methodology/approachThe results showed that in a channel cell, changing any geometric parameter may affect the temperature and flow field, even though the volume of the channel is kept constant. For a relatively small hydraulic diameter, microchannels with different angles have a similar dimensionless heat flux, while channels with bigger dimensions show various values of dimensionless heat flux. By increasing the angles of trapezoidal microchannels, dimensionless heat flux per unit of volume increases. As a result, the maximum and minimum heat transfer rate occurs in a trapezoidal microchannel with 75° and 30 internal’s, respectively. In the study of dimensionless heat flux rate with hydraulic diameter variations, an optimum hydraulic diameter (Dh) was observed in which the heat transfer rate per unit volume attains maximum value.FindingsThis optimum state is predicted to happen at a side angle of 75° and hydraulic diameter of 290 µm. In addition, in trapezoidal microchannel with higher aspect ratio, dimensionless heat flux rate is lower. Changing side angles of the channels and pressure drop have the same effect on pressure drop. For a constant pressure drop, if changing the side angles causes an increase in the rectangular area of the channel cross-section and the effect of the sides are not felt by the fluid, then the dimensionless heat flux will increase. By increasing the internal aspect ratio (t_2/t_3), the amount of t_3 decreases, and consequently, the conduction resistance of the hot surface decreases.Originality/valueThe effects of geometry of the microchannel, including internal and external dimensions on the behavior of heat transfer and fluid flow for pressure ranges between 2 and 8 kPa.

Numerical investigation of fluid flow and heat transfer in trapezoidal microchannel with groove structure

Numerical analysis of fluid flow and heat transfer in a trapezoidal microchannel was done using finite volume method for the range of Reynolds number 96 to 720. Three-dimensional simulations were carried out at constant heat flux and different pressure drop conditions to determine the optimum heat flux distributions across the microchannels. Further, the added effects of rectangular and semi-circular type grooves fabricated inside the microchannel were investigated. For the validation of numerical simulation of the rectangular and trapezoidal microchannel, pressure drop is measured for wide range of Reynolds number experimentally and found comparison well. Heat transfer, Nusselt number and performance factors were calculated from simulations for both microchannel. It was observed that the heat transfer in the trapezoidal shaped microchannel significantly increased by 12%, compared with the rectangular shaped microchannel. The average Nusselt number were found to be of a high value with increase in Reynolds number as well as channel perturbations due to the presence of grooves on the channel walls. Furthermore, the enhanced effects of size and number of grooves were systematically analyzed in the trapezoidal microchannel.