Study on Laminar Natural Convection Heat Transfer from a Hemisphere with Uniform Heat Flux Surface

Zhang, Jian; Liu, Jie; Lu, Weiyue

doi:10.1007/s11630-018-1051-y

Cited by 11 publications

(5 citation statements)

References 26 publications

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“…The buoyant air rises upwards from the concave surface, and the thermal plume is also uprising. For higher Ra (=10 7 ), entropy generation also increases in the vertical direction.…”

Section: Impact Of Ra On Isotherms and Streamlinesmentioning

confidence: 97%

“…Liu et al 6 studied the solid hemisphere with a flat surface downward in natural convection with the adiabatic plane and isothermal hemispherical surface. Zhang et al 7 performed their study on hemispherical surfaces with the iso-heat-flux condition. The analysis showed that both local and average Nusselt number is dependent on the Grashof number.…”

Section: Introductionmentioning

confidence: 99%

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Entropy production analysis and cooling time calculation for an open hemispherical cavity in natural convection

Behera

Chandrakar

Mukherjee

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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A numerical investigation of natural convection from an open hemispherical cavity is conducted in this study. The entropy production analysis and estimation of cooling time is the prime objective here. The study is conducted for different Rayleigh numbers [Formula: see text], the surface temperatures (350–550 K) and radius of curvature ratios of the hemisphere vary from 1 to 5. The problem is simulated in ANSYS Fluent 19. The perspective of both the first and second thermodynamic law is included in the modified function ( I/Q) to make the analysis. Entropy production because of fluid friction and heat transfer and corresponding irreversibilities are calculated, and obtained results are compared with the thermo-fluid behavior of the problem. The heat transfer enhances with an increment in the curvature radius and Rayleigh number for the given temperature. Also, entropy production, mainly contributed by heat transfer and fluid friction, has a lesser contribution. When the non-dimensional radius rises from 1 to 5, the dimensionless heat transfer increases from 5 to 24.05, almost five times for Ra = 103 and T* = 1.67. The entropy generation grows from 0.0011 to 0.0147 W/K when the non-dimensional temperature rises from 1.17 to 1.67 for R* = 5 and Ra = 103. A similar observation for Ra = 107 is noticed. With an increase in non-dimensional radius, the entropy generation rate increases up to five times. Moreover, the induced heat transfer irreversibility rises with the curvature radius, whereas fluid friction irreversibility reduces. The cooling time of the body is computed using lumped capacitance method.

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“…The buoyant air rises upwards from the concave surface, and the thermal plume is also uprising. For higher Ra (=10 7 ), entropy generation also increases in the vertical direction.…”

Section: Impact Of Ra On Isotherms and Streamlinesmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Entropy production analysis and cooling time calculation for an open hemispherical cavity in natural convection

Behera

Chandrakar

Mukherjee

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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show abstract

“…As they provide a means to advance our understanding of the coupled heat and momentum transfer in thermal fluid flow applications, numerous studies have focused on nonintrusive measurement techniques that simultaneously quantify velocity and/or temperature fields in experimental fluid dynamics (see, e.g., Yarin 2007;Tagawa et al 2001;Lavieille et al 2000;Fujisawa et al 2005). In this context, particle image velocimetry (PIV Westerweel 1997) and laser induced fluorescence (LIF, Walker 1987;Coppeta and Rogers 1998) are whole-field non-intrusive state-of-the-art measurement techniques that have been widely employed to quantify velocity and temperature fields, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…After splitting (or de-bayering) the information of each acquisition into R,G, and B images, we analyze the particle images pairs by means of state-of-theart PIV algorithms (Raffael et al 2018) to reconstruct the fluid velocity field. At the same time, the fluorescence signal recorded by one or more color channels can be used to recover the temperature field (Yarin 2007). This approach allows us to reduce the complexity and the cost of the setup by minimizing the number of components.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous PIV–LIF measurements using RuPhen and a color camera

Shah,

Mucignat,

Lunati

et al. 2023

Exp Fluids

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Particle image velocimetry (PIV) and laser-induced fluorescence (LIF) are currently state-of-the-art, non-intrusive measurement techniques that help in our understanding of heat and momentum transfer in thermal fluid flow applications. We present a simplified, integrated PIV–LIF system which simultaneously measures velocity and temperature fields in aqueous flows by means of a novel fluorescent dye (RuPhen), a low-cost continuous-wave diode laser, and a single color camera. We demonstrate that RuPhen is well-suited for this approach due to its peak absorption at 450 nm, peak emission at 605 nm, and a strong temperature-dependent emission with a sensitivity coefficient of $$4\%/^{\circ }\hbox {C}$$ 4 % / ∘ C . The large Stokes shift between excitation (which also includes Mie scattering of the flow tracers) and the emission facilitates the handling of the signal components in the RGB channels of the camera. To correct the recordings for laser power fluctuations, we propose a novel method that jointly employs two photoluminescence signals. We provide a spectral characterization of the dye at different temperatures and discuss the choice of each component for our measurement system. We demonstrate the potential of our approach by two experimental test cases that focus on thermally driven and turbulent flow regimes.

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“…Behaviour of micropolar Casson fluid on the flow of steady magnetohydrodynamic natural convection over a solid sphere has been described numerically by Alkasasbeh [12]. Further works interested in the discussion of natural convection heat transfer of fluid flow around the spheres are studied by [13,14]. More papers involved the studying of non-Newtonian Casson fluid flow with assorted circumstances are mentioned in the following sections.…”

Section: Introductionmentioning

confidence: 99%

Laminar MHD natural convection flow due to non-Newtonian nanofluid with dust nanoparticles around an isothermal sphere: Non-similar solution

Mohamed¹,

Hady²,

Mahdy³

et al. 2021

Phys. Scr.

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The focus of this paper is to examine non-similar solutions of dusty non-Newtonian Casson nanofluid flow around the surface of an isothermal sphere in the presence of magnetic field impact. It is presupposed that the impacts of thermophoresis and Brownian motion are considered into regard in the nanofluid model. In addition to the thermophoresis impact, the normal flux of nanoparticles is equal to zero at the boundary. With respect to the fluid temperature, the surface of the isothermal sphere is preserved at a constant temperature. The dust particles preassumed to having the same size and conform in the spherical shape to the nanoparticles. Suitable non-similarity transformations are utilized to mutate the governing partial differential equations for fluid and dust phases into a system of non-linear, coupled, and non-similar partial differential equations. The generated non-similar equations are solved using numerical technique renown MATLAB function bvp4c and the results are represented in terms of velocity and temperature of fluid and dust phases, and concentration distribution as well as the skin-friction coefficient and heat transfer rate. Obtained results indicate that increasing the mass concentration of the dust particles in the nanofluid leads to depression the motion and an enhancement in the rate of heat transfer. For the nanofluid phase and dust particle phase, the temperature magnitude improves with increasing of the stream wise coordinate additionally the distribution of velocity accelerates away from the sphere surface i.e. with high values of the radial coordinate η. Nomenclature a Radius of the sphere (m) B 0 Constant of magnetic field (kg −1 s −2 A −1 ) C Dimensional concentration C f Skin-friction coefficient c p Specific heat at constant pressure (J/kgK) c s Specific heat of particle phase (J/kgK) D B Brownian diffusion coefficient (m 2 s −1 ) D T Thermophoretic diffusion coefficient (m 2 s −1 ) D ρ Mass concentration of the dust particle Ec Eckert number e ij Deformation rate component f Dimensionless stream function for fluid velocityRECEIVED

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Study on Laminar Natural Convection Heat Transfer from a Hemisphere with Uniform Heat Flux Surface

Cited by 11 publications

References 26 publications

Entropy production analysis and cooling time calculation for an open hemispherical cavity in natural convection

Entropy production analysis and cooling time calculation for an open hemispherical cavity in natural convection

Simultaneous PIV–LIF measurements using RuPhen and a color camera

Laminar MHD natural convection flow due to non-Newtonian nanofluid with dust nanoparticles around an isothermal sphere: Non-similar solution

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