Showing papers on "Pressure drop published in 2017"
192 citations
TL;DR: In this article, heat transfer and pressure drop characteristic associated with minichannel heat sink is investigated experimentally and the results indicate that TiO2 nanofluid thermal performance is strongly dependent on heating power and its usefulness heat transfer characteristic could be achieved more effectively at lower heating power.
176 citations
TL;DR: In this article, a three-dimensional flow field (WSFF), patterned with waved serpentine flow channels, is designed and analyzed by combing the simulating method with experimental method.
170 citations
TL;DR: In this paper, the computational fluid dynamics of laminar flow and heat transfer in an indented microchannel is investigated, where water/TiO 2 nanofluid has been used as a working fluid.
156 citations
TL;DR: In this article, a three-dimensional numerical simulation was conducted to study the characteristics of fluid flow and heat transfer in new design of microchannel heat sink with sinusoidal cavities and rectangular ribs (MC-SCRR) for Reynolds number ranging from 100 to 800.
152 citations
TL;DR: In this paper, the behavior of non-Newtonian nanofluid hydrodynamic and heat transfer is simulated and the effect of volume fraction of the nanoparticles, Reynolds number, Nusselt number, dimensionless temperature, and heat-transfer coefficient is analyzed.
Abstract: In this investigation, the behavior of non-Newtonian nanofluid hydrodynamic and heat transfer are simulated. In this study, we numerically simulated a laminar forced non-Newtonian nanofluid flow containing a 0.5 wt% carboxy methyl cellulose (CMC) solutionin water as the base fluid with alumina at volume fractions of 0.5 and 1.5 as the solid nanoparticle. Numerical solution was modelled in Cartesian coordinate system in a two-dimensional microchannel in Reynolds number range of 10≤Re≤1000. The analyzed geometrical space here was a rectangular part of whose upper and bottom walls was influenced by a constant temperature. The effect of volume fraction of the nanoparticles, Reynolds number and non-Newtonian nanofluids was studied. In this research, the changes pressure drop, the Nusselt number, dimensionless temperature and heat transfer coefficient, caused by the motion of non-Newtonian nanofluids are described. The results indicated that the increase of the volume fraction of the solid nanoparticles and a reduction in the diameter of the nanoparticles would improve heat transfer which is more significant in Reynolds number. The results of the introduced parameters in the form of graphs drawing and for different parameters are compared.
152 citations
TL;DR: In this paper, the performance of proton exchange membrane fuel cells is studied for three cases; a fuel cell with two parallel flow channels, locally baffle restricted flow channels and metal foam as a flow distributor.
136 citations
TL;DR: In this article, the effect of attack angle of ribs and Al2O3 nanoparticles on the heat transfer enhancement was investigated and the results showed that the presence of ribs with the creation of eddy on the direction of flow causes better mixture of flow and consequently, heat transfer increases and adding nanoparticles to the base flow causes more augment of heat transfer.
127 citations
TL;DR: A novel sliding mode control based high-precision hydraulic pressure feedback modulation based on an open loop load pressure control based on the linear relationship between the pressure-drop and coil current in valve critical open equilibrium state is proposed and experimentally validated.
Abstract: High precision and fast response are of great significance for hydraulic pressure control in automotive braking systems. In this paper, a novel sliding mode control based high-precision hydraulic pressure feedback modulation is proposed. Dynamical models of the hydraulic brake system including valve dynamics are established. An open loop load pressure control based on the linear relationship between the pressure-drop and coil current in valve critical open equilibrium state is proposed, and also experimentally validated on a hardware-in-the-loop test rig. The control characteristics under different input pressures and varied coil currents are investigated. Moreover, the sensitivity of the proposed modulation on valve's key structure parameters and environmental temperatures are explored with some unexpected drawbacks. In order to achieve better robustness and precision, a sliding mode control based closed loop scheme is developed for the linear pressure-drop modulation. Comparative tests between this method and the existing methods are carried out. The results validate the effectiveness and superior performance of the proposed closed loop modulation method.
121 citations
TL;DR: In this paper, a perforated vortex generator (PVG) was developed to improve convection heat transfer in a circular tube in turbulent flow regime with the Reynolds number over the range 3000-21,000 using air as the working fluid under uniform wall heat flux boundary condition.
120 citations
TL;DR: In this paper, the Equal Path Length (EPL) flow field architecture was proposed and evaluated, which has superior mass transport characteristics in comparison with the standard serpentine and interdigitated designs at the expense of increased pressure drop.
TL;DR: In this article, the heat transfer performance of the micro-channel heat sinks with five different pin-fin configurations were investigated numerically and experimentally, and the computational fluid dynamics simulations showed that the pin fin shape changes the thermo-fluid characteristics of a microchannel heat sink inducing the lowest thermal resistance and uniformity of the chip's top surface (UCTS).
TL;DR: In this article, the authors investigate the thermal performance of a cooling liquid block working with gallium, CuO/water nanofluid and water and show that gallium is the most efficient coolant amongst the nanofluid and water in terms of convective thermal performance.
TL;DR: In this paper, the thermal performance of a nanofluid flow through a flat plate solar collector with the metal porous foam filled channel is experimentally investigated, and the performance evaluation criterion (PEC) has been used for both the SiO2 and porous media separately.
TL;DR: In this paper, the utilization of internally finned absorbers in LS-2 PTC module for various operating conditions was investigated and compared with the smooth case with 12 different longitudinal fin lengths and 2mm fin thickness.
TL;DR: In this article, the effect of varying the flow rate (i.e. velocity) on the pressure drop for each of the designs modelled was analyzed. And the results showed that a modification of fuel cell designs in existence using a system similar to the diesel injection system design approach reduced pressure drop in the fuel cell as shown by the simulation results.
TL;DR: In this paper, the impact of feed spacer design on membrane performance is investigated by means of three-dimensional (3D) computational fluid dynamics (CFD) simulations, where the solution-diffusion model is employed for water and solute transport through RO membranes.
TL;DR: In this article, a wavy-tape insert was used for the parabolic trough receiver (PTR) to improve its performances by enhancing the heat transfer inside the absorber tube.
TL;DR: In this article, the effect of using water/graphene oxide nanofluid as a working fluid on heat transfer and pressure drop was studied experimentally in a tube under air cross-flow.
TL;DR: In this paper, a new design of wavy microchannel heat sink with porous fins is proposed to reduce simultaneously pressure drop and thermal resistance, which is attributed to the combination of the enhanced coolant mixing by Dean vortices, the prolonged flow route by increasing equivalent channel length, and the forced permeation by jet-like impingement.
TL;DR: The hypothesis that for an efficient oxygen up-regulation at least two regulation mechanisms must be playing hand in hand, namely cerebral blood flow increase and microvascular flow homogenization is supported, however, the contribution of both regulation mechanisms to oxygenUp-regulation likely varies over depth.
Abstract: A better knowledge of the flow and pressure distribution in realistic microvascular networks is needed for improving our understanding of neurovascular coupling mechanisms and the related measurement techniques. Here, numerical simulations with discrete tracking of red blood cells (RBCs) are performed in three realistic microvascular networks from the mouse cerebral cortex. Our analysis is based on trajectories of individual RBCs and focuses on layer-specific flow phenomena until a cortical depth of 1 mm. The individual RBC trajectories reveal that in the capillary bed RBCs preferentially move in plane. Hence, the capillary flow field shows laminar patterns and a layer-specific analysis is valid. We demonstrate that for RBCs entering the capillary bed close to the cortical surface (< 400 μm) the largest pressure drop takes place in the capillaries (37%), while for deeper regions arterioles are responsible for 61% of the total pressure drop. Further flow characteristics, such as capillary transit time or RBC velocity, also vary significantly over cortical depth. Comparison of purely topological characteristics with flow-based ones shows that a combined interpretation of topology and flow is indispensable. Our results provide evidence that it is crucial to consider layer-specific differences for all investigations related to the flow and pressure distribution in the cortical vasculature. These findings support the hypothesis that for an efficient oxygen up-regulation at least two regulation mechanisms must be playing hand in hand, namely cerebral blood flow increase and microvascular flow homogenization. However, the contribution of both regulation mechanisms to oxygen up-regulation likely varies over depth.
TL;DR: The mechanism of this elastic instability is presented and characterize it based on the pressure drop fluctuation spectral density, and the size of stationary dead zones correlates with the level of shear-thinning, by varying the amount of salt in HPAM solution.
Abstract: We experimentally investigate the flow of hydrolyzed polyacrylamide (HPAM) solution with and without salt in model porous media at high Weissenberg numbers (Wi > 1.0). The effect of pore shapes on the flow pattern and pressure drop is explored by using periodic arrays of circular and square pillars in aligned and staggered layouts. In the apparent shear-thinning regime, we observe stationary dead zones upstream of the pillars. In addition, we confirm that the size of stationary dead zones correlates with the level of shear-thinning, by varying the amount of salt in HPAM solution. At higher shear rates (or Wi), these dead zones are periodically washed away. We present the mechanism of this elastic instability and characterize it based on the pressure drop fluctuation spectral density.
TL;DR: In this article, the effect of relative ribs pitch and relative ribs height on Nusselt number and friction factor have been studied for the range of Reynolds number from 4000 to 16,000.
TL;DR: In this paper, the KD2 Pro Thermal Properties Analyzer was employed to measure thermal conductivity of the prepared samples at different temperatures and showed that the thermal conductivities improved proportionally with augmenting the concentration and temperature.
TL;DR: In this article, the effect of three geometrical parameters; relative width of secondary channel (λ), relative rib width (β), and angle of secondary channels (θ) on the convective heat transfer and pressure drop have been investigated.
TL;DR: In this article, the effect of cyclone arrangements on the gas-solid flow dynamics in the three-dimensional full-loop CFB is investigated by the computational fluid dynamics coupled with discrete element method (CFD-DEM).
TL;DR: In this paper, the authors evaluated hole cleaning efficiency of an oil-based drilling fluid (OBM) and a water-based fluid (WBM) whose viscosity profiles are similar as per API specifications.
TL;DR: In this paper, the performance of a proton exchange membrane fuel cell (PEMFC) was simulated with cooling flow field simultaneously with two conventional serpentine and parallel types of flow field of cooling plates.
TL;DR: In this paper, the authors deal with the post-processing of experimental data on the flow and heat transfer in a nanofluid-based double tube heat exchanger using an artificial neural network.
TL;DR: In this article, a multi-objective optimization of a classic Stairmand cyclone separator is executed using the response surface methodology (RSM), combined with computational fluid dynamics (CFD) techniques for minimizing the pressure drop and maximizing the collection efficiency.