Friction factor and Nusselt number correlations for forced convection in helical tubes

Zhao, Houjian; Li, Xiaowei; Wu, Yingjie; Wu, Xinxin

doi:10.1016/j.ijheatmasstransfer.2020.119759

Cited by 33 publications

(10 citation statements)

References 57 publications

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“…Based on the fundamental restrictions of the geometry, parametric modifications to the equation determining the Nusselt number (Eq. ( 18)) need to be considered based on constant wall temperature assumptions [46], curvature ration [47], and fluid regime [48] such that:…”

Section: Resultsmentioning

confidence: 99%

Numerical Analysis of a Water-Cooled Condenser at Startup Conditions for Refrigeration Applications Supported with Experiments

Acosta¹

2021

Heat Transfer - Design, Experimentation and Applications

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Refrigeration for commercial purposes is one of the industrial sectors with the largest energy consumption in the global market. Therefore, research and development of more efficient components such as compressors, condensers, and refrigerants continue to render promising results in terms of GWP and operational costs. However, Due to the urgency typically found in industry to develop prototypes, finding scalable solutions can be challenging. Arguably, this is the case for condenser and evaporators that are designed and assembled under the assumption that refrigeration systems operate at steady condition, where in real circumstances such systems operate under transients based on ambient temperatures or unfavorable startup conditions. The aim of this study is to characterize the thermal and fluid dynamics behavior of refrigerant R404a in a water-cooled condenser at startup conditions. The boundary conditions to solve the CFD simulations are taken from experimental values and set as user defined functions in a commercial software. The results displayed the time dependent oscillatory phase-transition details of the refrigerant throughout the domain.

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Section: Resultsmentioning

confidence: 99%

Numerical Analysis of a Water-Cooled Condenser at Startup Conditions for Refrigeration Applications Supported with Experiments

Acosta¹

2021

Heat Transfer - Design, Experimentation and Applications

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“…At an exact flow condition, Dean vortices appearing near the outside bowlshaped wall of the channel, called by the name of Dean (1927). After that, significant studies on analytical, numerical and experimental inquiries have been done; here the researches are mentioned to Mondal et al (2006Mondal et al ( , 2007a, Yamamoto et al (2006), Zhao et al (2020) and Nowruzi et al (2019) for a number of excellent reviews on curved channel flows.…”

Section: Introductionmentioning

confidence: 99%

“…Nowruzi et al (2019) applied Homotopy perturbation method to investigate hydrodynamic instability in a curved channel of different aspect ratio for several curvatures. Recently, Zhao et al (2020) illustrated the influence of friction factor and Nusselt number in terms of time instead of large Reynolds numbers and curvature ratios. Mondal et al (2013Mondal et al ( , 2014 and demonstrated the structural change of flow velocity and isotherms in terms of changing the time.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Features of Laminar Viscous Incompressible Flow and Temperature Dissemination through a Rotating Bent Rectangular Channel: The Case of Negative Rotation

Adhikari¹,

Hasan

Akter³

et al. 2023

Preprint

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The current study investigates the effects of rotation on fluid flow and heat transfer through a curved channel of rectangular cross-section with bottom wall heated and cooling from the top. A wide range of the Taylor number with constant curvature = 0.2, aspect ratio 2 and the Prandtl number Pr = 7.0 (water) have been considered for the study. After a broad investigation to explore transient flow behavior, time-history analysis is performed using phase trajectory of the transient solutions at fully developed stage. As a result, the stages of transient flow endure in the consequence “chaotic → periodic → multi-periodic → chaotic” for the rotating system in the negative direction comprising with 2- to 8- vortex solutions. It is further illustrated from stream function and energy distribution that the heat transfer is ominously enhanced at high rotation and the chaotic flow enhances heat transfer more significantly than the steady-state, periodic or other physically realizable solutions. Finally, the current numerical results are compared with laboratory-based experimental results and a good agreement is observed.

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“…They discussed the steady and unsteady solutions with linear stability and found that SF enhances CHT significantly, and the chaotic flow, which occurs at large Dn's, enhances HT more efficiently than the other US. Recently, Zhao et al [32] illustrated the influence of friction factor and Nusselt number in terms of time instead of curvature ratios and large Reynolds numbers. Very recently, Chanda et al [26] discussed the CHT for rotating BRD flow, and they obtained the nearly same result as obtained by Hasan et al [33].…”

Section: Introductionmentioning

confidence: 99%

Pressure-Induced Instability Characteristics of a Transient Flow and Energy Distribution through a Loosely Bent Square Duct

Adhikari¹,

Chanda²,

Bhowmick³

et al. 2022

Energy Engineering

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Friction factor and Nusselt number correlations for forced convection in helical tubes

Cited by 33 publications

References 57 publications

Numerical Analysis of a Water-Cooled Condenser at Startup Conditions for Refrigeration Applications Supported with Experiments

Numerical Analysis of a Water-Cooled Condenser at Startup Conditions for Refrigeration Applications Supported with Experiments

Unsteady Features of Laminar Viscous Incompressible Flow and Temperature Dissemination through a Rotating Bent Rectangular Channel: The Case of Negative Rotation

Pressure-Induced Instability Characteristics of a Transient Flow and Energy Distribution through a Loosely Bent Square Duct

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