Numerical study of laminar natural convection heat transfer from a hemisphere with adiabatic plane and isothermal hemispherical surface

Liu, Jie; Zhao, Can-Jun; Liu, Huan; Lu, Weiyue

doi:10.1016/j.ijthermalsci.2018.05.013

Cited by 16 publications

(4 citation statements)

References 43 publications

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“…The current scheme is validated with the experimental data of Hassani and Hollands, 4 free convection from an isothermal sphere, and computational outcomes of Liu et al, 6 which is free convective heat loss from an open hemispherical cavity with a constant surface temperature. Figure 2(a) shows the plot of average Nu with Ra and Figure 2(b) shows the variation of average Nu with Gr .…”

Section: Numerical Proceduresmentioning

confidence: 69%

“…(a) Plot of Nu with Ra : comparing with the experimental data of Hassani and Hollands 4 for a constant temperature sphere and (b) variation of Nu with Gr : comparing with the numerical outcomes of Liu et al 6 for the isothermal open hemispherical cavity.…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…The authors proposed new correlations for Nu to quantify the convective heat loss. 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.…”

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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Section: Numerical Proceduresmentioning

confidence: 69%

Section: Numerical Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

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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“…In the case of the trapezoidal solar cavity, radiative heat losses are reported to be dominantly contributing almost about 70–80% of the total receiver losses and the rest 20–30% is contributed by the convective mode (Nayak et al , 2018). The free convection phenomenon has been studied numerically by Liu et al (2018) inside the isothermal hemisphere shaped cavity receiver, with air as an enclosed medium. The Nusselt number estimated at a corner location is reported to be maximum that showed a reducing trend toward the corner of the hemisphere shaped cavity.…”

Section: Introductionmentioning

confidence: 99%

Thermal performance analysis of a Solar parabolic dish concentrator system with modified cavity receiver

Kumar

Bopche

2021

WJE

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Purpose This paper aims to present the numerical models and experimental outcomes pertain to the performance of the parabolic dish concentrator system with a modified cavity-type receiver (hemispherical-shaped). Design/methodology/approach The numerical models were evolved based on two types of boundary conditions; isothermal receiver surface and non-isothermal receiver surface. For validation of the numerical models with experimental results, three statistical terms were used: mean of absolute deviation, R2 and root mean square error. Findings The thermal efficiency of the receiver values obtained using the numerical model with a non-isothermal receiver surface found agreeing well with experimental results. The numerical model with non-isothermal surface boundary condition exhibited more accurate results as compared to that with isothermal surface boundary condition. The receiver heat loss analysis based on the experimental outcomes is also carried out to estimate the contributions of various modes of heat transfer. The losses by radiation, convection and conduction contribute about 27.47%, 70.89% and 1.83%, in the total receiver loss, respectively. Practical implications An empirical correlation based on experimental data is also presented to anticipate the effect of studied parameters on the receiver collection efficiency. The anticipations may help to adopt the technology for practical use. Social implications The developed models would help to design and anticipating the performance of the dish concentrator system with a modified cavity receiver that may be used for applications e.g. power generation, water heating, air-conditioning, solar cooking, solar drying, energy storage, etc. Originality/value The originality of this manuscript comprising presenting a differential-mathematical analysis/modeling of hemispherical shaped modified cavity receiver with non-uniform surface temperature boundary condition. It can estimate the variation of temperature of heat transfer fluid (water) along with the receiver height, by taking into account the receiver cavity losses by means of radiation and convection modes. The model also considers the radiative heat exchange among the internal ring-surface elements of the cavity.

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A Numerical Method to Analyze the Steady Conjugate Heat Transfer Around a Slab Suspended in Air

Rana

Patel

Ukamanal

et al. 2022

Recent Advances in Thermofluids and Manufacturing Engineering

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Numerical study of laminar natural convection heat transfer from a hemisphere with adiabatic plane and isothermal hemispherical surface

Cited by 16 publications

References 43 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

Thermal performance analysis of a Solar parabolic dish concentrator system with modified cavity receiver

A Numerical Method to Analyze the Steady Conjugate Heat Transfer Around a Slab Suspended in Air

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