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Maryam Fallah Najafabadi

Bio: Maryam Fallah Najafabadi is an academic researcher from Babol Noshirvani University of Technology. The author has contributed to research in topics: Heat transfer & Mechanics. The author has an hindex of 1, co-authored 3 publications receiving 3 citations.

Papers
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TL;DR: In this article , the effect of parameters, including Grashof number, Brownian motion parameter, etc., on the motion, velocity, temperature, and volume fraction of nanofluids have been analyzed.

19 citations

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TL;DR: In this paper, a twisted double-pipe heat exchanger containing phase change material is designed and analyzed as an energy storage unit in solar collectors, and the effects of several parameters like pipe's position, twisting, and cross-section on the PCM melting in the storage unit have been investigated.

10 citations

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TL;DR: In this paper , the authors investigated the motion, temperature and volume fraction of a nanofluid that flows at a vertical channel exposed to natural and forced (mixed) convection heat transfer.
Abstract: Our study investigates the motion, temperature and volume fraction of a nanofluid that flows at a vertical channel exposed to natural and forced (mixed) convection heat transfer. The distribution function for temperature and volume fraction on the channel's wall is exponential. Nanofluid governing equations have been solved using the radial basis function method. Various parameters, including Grashof number, Brownian motion, thermophoresis parameter, plus distinct states for temperature and volume fraction functions for the channel's wall, have been probed. The results show that increasing the Grashof number by 50% will increase the fluid velocity and temperature by about 41% and 5.7% and decrease the volume fraction by 22%. In addition, it has been proved that doubling the Brownian motion parameter improves the fluid temperature and velocity by 67% and 66% and lowers the volume fraction by 53%. Moreover, increasing the thermophoresis parameter has a similar effect to the Brownian motion parameter. Finally, it has been seen that velocity, temperature and volume fraction functions strongly depend on temperature and volume fraction distribution functions on the channel's wall.

7 citations

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TL;DR: In this article , a 3D double-pipe helical coil heat exchanger containing phase-change material (PCM) was investigated as a thermal storage system in solar water heaters, and the impact of some critical geometrical parameters, like helical pitch, inner and outer pipe diameter, and some flow parameters, such as fluid inlet temperature and Reynolds number, were analyzed.
Abstract: This research investigates a 3-D double-pipe helical coil heat exchanger containing Phase-Change Material (PCM) as a thermal storage system in solar water heaters. A concentric double-pipe follows the helical profile upward and creates a heat storage unit. In the unit, water in turbulent mode flows in the inner pipe as a Heat Transfer Fluid (HTF), and RT-50 is considered PCM placed in the annulus. This heat exchanger with all related conditions is modeled in Ansys Fluent 19 software, and we used the k-ε RNG turbulence model to simulate turbulent flow. For evaluating this novel model of thermal storage unit, the impact of some critical geometrical parameters, like helical pitch, inner and outer pipe diameter, and some flow parameters, such as fluid inlet temperature and Reynolds number, have been analyzed. The most important outcomes of the investigation show that inlet temperature and inner and outer pipe diameter are critical factors for the storage system's design. A 1.5 % change in inlet temperature will enhance the melting rate by 27 %. Also, by increasing the inner pipe diameter by 42 %, the melting process was improved by 92 %, while the outer pipe diameter was inversely related to the melting rate. A 20 % increase in this parameter's value showed a 52 % reduction in the melting. Moreover, the change in the helical pitch could not significantly affect the PCM melting process, and for a 300 % increase in pitch size, the melting process increases only by 0.6 %. • PCM melting in double-pipe helical coil TES unit in a solar water heater is studied. • With turbulent HTF flow, the Reynolds number has no major effect on the melting. • Increasing HTF inlet temperature or inner coil diameter increases the melting rate. • Reducing the outer pipe diameter increases the PCM melting process. • The helical pitch has no significant effect on the melting rate.

6 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper , the authors analyzed the flow of ternary nanofluid past a stretching sheet subjected to Thomson and Troian slip condition along with the temperature jump, and the results indicated that the increase in the suspension of silver nanoparticles enhanced the temperature and due to density, the velocity of the flow is reduced.
Abstract: Abstract In this article, the flow of ternary nanofluid is analysed past a stretching sheet subjected to Thomson and Troian slip condition along with the temperature jump. The ternary nanofluid is formed by suspending three different types of nanoparticles namely $$\text{TiO}_{2}, \text{Cu}$$ TiO 2 , Cu and $$\text{Ag}$$ Ag into water which acts as a base fluid and leads to the motion of nanoparticles. The high thermal conductivity and chemical stability of silver was the main cause for its suspension as the third nanoparticle into the hybrid nanofluid $$\text{Cu-TiO}_{2}/\text{H}_{2} \text{O}$$ Cu-TiO 2 / H 2 O . Thus, forming the ternary nanofluid $$\text{Ag-Cu-TiO}_{2}/\text{H}_{2} \text{O}$$ Ag-Cu-TiO 2 / H 2 O . The sheet is assumed to be vertically stretching where the gravitational force will have its impact in the form of free convection. Furthermore, the presence of radiation and heat source/sink is assumed so that the energy equation thus formed will be similar to most of the real life applications. The assumption mentioned here leads to the mathematical model framed using partial differential equations (PDE) which are further transformed to ordinary differential equations (ODE) using suitable similarity transformations. Thus, obtained system of equations is solved by incorporating the RKF-45 numerical technique. The results indicated that the increase in the suspension of silver nanoparticles enhanced the temperature and due to density, the velocity of the flow is reduced. The slip in the velocity decreased the flow speed while the temperature of the nanofluid was observed to be increasing.

28 citations

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TL;DR: In this paper , the authors considered temperature variation through an inclined porous longitudinal fine with convective radiative phenomenon and applied differential transform method (DTM) with Pade approximant for the radiation heat exchange.

27 citations

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TL;DR: In this paper , the von Karman approach is applied to convert partial derivative form of governing nonlinear transport equations into ordinary derivative form and is then evaluated by using an efficient boundary value problem (BVP4c) solver.

24 citations

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TL;DR: In this paper , an innovative anchor-type longitudinal fin design that copes with the sluggish phase change process in shell-and-tube ice storage units by covering the regions between the conventional fin is introduced.

23 citations

Journal ArticleDOI
TL;DR: In this article , the effect of parameters, including Grashof number, Brownian motion parameter, etc., on the motion, velocity, temperature, and volume fraction of nanofluids have been analyzed.

19 citations