Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems

Jiadingzhen, China

Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems

Jiadingzhen, China
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Jin Z.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Jin Z.,Tongji University | Zhang H.,Tongji University | Yang Z.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems
International Journal of Heat and Mass Transfer | Year: 2017

In the present study, we report for the first time the detailed dynamic motions of a water droplet impacting on an ice surface. Besides, the effects of the initial height of the water droplet and the ice surface temperature on the impact and freezing processes of the water droplet were experimentally investigated. During the experiment, an ice surface was generated first and then kept at a desired temperature by a constant temperature bath circulator. After that, a deionized water droplet was deposited onto the ice surface and its impact and freezing processes were recorded. The results showed that, during the impact process of the water droplet, once the water droplet reached its maximum contact diameter, the contact line of the water droplet was pinned on the ice surface without recoiling. Besides, at the same initial height of the water droplet, the decrease of the ice surface temperature resulted in the reduction of the maximum spreading factor and an apparent increase of the height of the ice bead. Moreover, once the droplet initial height was increased, the maximum spreading factor increased while the height of the ice bead reduced significantly. © 2017 Elsevier Ltd


Zohurul Islam M.,Jessore University of Science and Technology | Mondal R.N.,Jagannath University | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Computers and Fluids | Year: 2017

Due to engineering application and its intricacy, flow in a rotating coiled duct has become one of the most challenging research fields of fluid mechanics. In this paper, a spectral-based numerical study is presented for the fully developed two-dimensional flow of viscous incompressible fluid through a rotating coiled rectangular duct. The emerging parameters controlling the flow characteristics are the rotational parameter i.e. the Taylor number, Tr; the Grashof number, Gr; the Prandtl number, Pr and the pressure-driven parameter i.e. the Dean number, Dn. The rotation of the duct about the center of curvature is imposed in both the positive and negative direction and combined effects of the centrifugal, Coriolis and buoyancy forces are investigated, in detail, for two cases of the Dean Numbers, Case I: Dn = 1000 and Case II: Dn = 1500. For positive rotation, we investigated unsteady solutions for 0 ≤ Tr ≤ 500, and it is found that the chaotic flow turns into steady-state flow through periodic or multi-periodic flows, if Tr is increased in the positive direction. For negative rotation, however, unsteady solutions are investigated for −700≤Tr≤−50, and it is found that the unsteady flow undergoes through various flow instabilities, if Tr is increased in the negative direction. Typical contours of secondary flow patterns and temperature distributions are obtained at several values of Tr, and it is found that the unsteady flow consists of asymmetric two- to eight-vortex solutions. The present study demonstrates the role of secondary vortices on convective heat transfer and it is found that convective heat transfer is significantly enhanced by the secondary flow; and the chaotic flow, which occurs at large Dn's, enhances heat transfer more effectively than the steady-state or periodic solutions. This study also shows that there is a strong interaction between the heating-induced buoyancy force and the centrifugal-Coriolis instability in the curved channel that stimulates fluid mixing and consequently enhances heat transfer in the fluid. © 2017 Elsevier Ltd


Jin Z.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Jin Z.,Tongji University | Pasqualini S.,Tongji University | Yang Z.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems
European Journal of Mechanics, B/Fluids | Year: 2016

In the present study, an experimental study was conducted to characterize the flow structures in the turbulent wake of a cross parachute canopy by utilizing Stereoscopic Particle Image Velocimetry (Stereo-PIV) technique. Both flow through gap and flow over arm of the cross parachutes were carefully measured and analyzed. The obtained results showed that the turbulent wake of the flow through gap was larger than that of flow over arm. Besides, the distributions of velocity, vorticity, and Reynolds stress of flow through gap differed significantly with those of flow over arm. In addition, the effect of the arm ratio of the cross canopy on the transverse profiles of velocity, vorticity, and Reynolds stress was also discussed. © 2016 Elsevier Masson SAS


Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group | Nasiri M.,University of Tabriz | Khezerloo M.,University of Tabriz | Laraqi N.,Paris West University Nanterre La Défense
Journal of Magnetism and Magnetic Materials | Year: 2016

In this study, mixed convection heat transfer of nano-fluid flow in vertical channel with sinusoidal walls under magnetic field effect is investigated numerically. The heat transfer and hydrodynamic characteristics have been examined. This study has performed for 500≤Re≤1000, 5×104≤Gr≤1×106, three amplitude sine wave (0.1, 0.2 and 0.3) and three values of Hartman numbers (0, 5 and 10). Water was utilized as the base fluid and Al2O3 is the considered nano-particle. Flow is assumed two dimensional, laminar, steady and incompressible. As well the thermo-physical properties of nano-fluid are considered constant. The Boussinesq approximation used for calculated the density variations. The average Nusslet number increases by increasing the Grashof number for nano-fluids with different volume fraction. The average Nusselt and Poiseuille number increase as Reynolds number increases. Also, the average Nusselt number and Poiseuille number increases by increasing the Hartman number. © 2015 Elsevier B.V.


Garoosi F.,Semnan University | Garoosi F.,Islamic Azad University | Hoseininejad F.,Islamic Azad University | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Applied Thermal Engineering | Year: 2016

This article presents a numerical study of natural convection heat transfer in a heat exchanger filled with nanofluid. Walls of the enclosure are insulated and constant temperature conditions are given for hot (Th ) and cold (Tc ) pipes (Th >. Tc ). The effects of pertinent parameters such as; Rayleigh number, temperature of the nanofluid, diameter and type of the nanoparticles on the heat transfer rate are examined. Moreover, the influence of design parameters such as; arrangement and orientation of the hot and cold pipes, location and number of the hot pipe, internal and external cooling and heating on the flow field, temperature distributions and the heat transfer rate are also investigated. The results show that, the total Nusselt number enhances with increasing the nanoparticle volume fraction up to an optimal particle loading at which the heat transfer rate within the enclosure has a maximum value. In addition, the results indicated that, the heat transfer rate and the optimal particle loading enhances by increasing the average temperature of the nanofluid. Finally, the numerical results demonstrate that, location, arrangement and number of the hot and cold pipes have a significant impact on the heat transfer rate across the heat exchanger. © 2016 Elsevier Ltd.


Garoosi F.,Semnan University | Garoosi F.,Islamic Azad University | Hoseininejad F.,Islamic Azad University | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Energy | Year: 2016

Natural convection of nanofluids around several pairs of hot and cold cylinders in an adiabatic enclosure is investigated numerically. Hot and cold cylinders are maintained at the different constant temperatures (Th > Tc) while the walls of the enclosure are thermally insulated. A parametric study is undertaken to explore the effects of the pertinent parameters, such as; Rayleigh number, size and type of the nanoparticles, shape of the enclosure, orientation and number of the hot and cold cylinders on the fluid flow and heat transfer characteristic. The simulations show that at low Ra, by changing shape of the enclosure from square to triangular one, the heat transfer rate decreases. It is also found that at each Ra, there is an optimum volume fraction of nanoparticles (ϕopt) where the heat transfer rate within the enclosure has a maximum value. Moreover, the results of this study showed by altering orientation of the hot and cold cylinders from horizontal to vertical mode, the heat transfer rate enhances. Finally, the results indicated that, by decreasing the size of the nanoparticles, the heat transfer rate and optimal particle loading (ϕopt) enhances. © 2016 Elsevier Ltd


Sarwar S.,COMSATS Institute of Information Technology | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems
Waves in Random and Complex Media | Year: 2016

This paper deals with the investigation of the analytical approximate solutions for two-term fractional-order diffusion, wave-diffusion, and telegraph equations. The fractional derivatives are defined in the Caputo sense, whose orders belong to the intervals [0,1], (1,2), and [1,2], respectively. In this paper, we extended optimal homotopy asymptotic method (OHAM) for two-term fractional-order wave-diffusion equations. Highly approximate solution is obtained in series form using this extended method. Approximate solution obtained by OHAM is compared with the exact solution. It is observed that OHAM is a prevailing and convergent method for the solutions of nonlinear-fractional-order time-dependent partial differential problems. The numerical results rendering that the applied method is explicit, effective, and easy to use, for handling more general fractional-order wave diffusion, diffusion, and telegraph problems. © 2016 Taylor & Francis


Garoosi F.,Semnan University | Rohani B.,University of Technology Malaysia | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Powder Technology | Year: 2015

Steady state mixed convection heat transfer of nanofluid in a two-sided lid driven cavity with several pairs of heaters and coolers (HACs) inside is investigated numerically using two-phase mixture model. The governing equations have been discretized using the finite volume method while the SIMPLE algorithm has been introduced to couple the velocity-pressure. The influences of volume fraction, diameter and type of the nanoparticles, Richardson number, number of the Heaters and Coolers (HACs), external and internal heating and moving direction of the cavity walls on flow structure, the heat transfer rate and distribution of nanoparticles are investigated. The results of this investigation illustrate that, at low Richardson number by increasing number of the HACs, the heat transfer rate increases. On the other hand, at high Ri, a saturated number of HACs exists which beyond that the value of mean Nusselt number does not changes significantly. In addition, the results reveal that by reducing the diameter of the nanoparticles and Ri, the heat transfer rate increases. It is also observed that at high Richardson numbers, distribution of nanoparticles with dp≥145nm is fairly non-uniform while at low Richardson numbers particle distribution remains almost uniform. Moreover, it is found that by changing direction of the moving walls the heat transfer rate changes significantly. © 2015 Elsevier B.V.


Garoosi F.,Semnan University | Bagheri G.,University of Geneva | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Powder Technology | Year: 2015

A numerical study is carried out concerning natural and mixed convection heat transfer of nanofluid in a two-dimensional square cavity with several pairs of heat source-sinks. Two-dimensional Navier-Stokes, energy and volume fraction equations are solved using the finite volume method. Effects of various design parameters such as external and internal heating, number of the coolers, Rayleigh number (103≤Ra≤107), Richardson number (0.01≤Ri≤1000), nanoparticle volume fraction (0≤ϕ≤0.05), size (25nm≤dp≤145nm) and type (Cu, Al2O3, TiO2) on the heat transfer rate and distribution of nanoparticles are investigated. The simulation results indicate that there is an optimal volume fraction of the nanoparticles for each Rayleigh number and Richardson number at which the maximum heat transfer rate occurs. It is also observed that at low Rayleigh numbers and high Richardson numbers, the particle distribution is fairly non-uniform. Moreover, it is found that thermophoretic effects are negligible for nanoparticles with high thermal conductivity. As a result, in such conditions the use of homogeneous and single-phase models is valid at any Ra and Ri. © 2015 Elsevier B.V.


Kherbeet A.S.,University of Tenaga Nasional | Mohammed H.A.,University of Technology, Iraq | Salman B.H.,Limkokwing University of Creative Technology | Ahmed H.E.,University of Anbar | And 2 more authors.
Experimental Thermal and Fluid Science | Year: 2015

This paper investigates experimentally the effects of laminar nanofluid flow over the microscale backward-facing step (MBFS) and forward-facing step (MFFS) on the heat transfer characteristics. The experiments were implemented on MBFS and MFFS with a step height of 600μm. Both MBFS and MFFS have the upstream and downstream lengths of 0.1m and 0.15m respectively. The Reynolds number ranged of 280-480. The concentrations of SiO2 nanoparticle valued at 0.005 and 0.01 with a diameter of 30nm were immersed in a distilled water. The experimental results revealed that the concentration of 0.01 water-SiO2 nanofluid recorded the highest Nusselt number. The comparison between MBFS and MFFS revealed that the highest Nusselt number is obtained through the use of the MFFS, which is approximately twice that of MBFS. However, the friction factor recorded a higher value for MFFS. The experimental results were in a good agreement with the numerical published results. © 2015 Elsevier Inc.

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