Numerical modeling of flow structure and heat transfer in a mist turbulent flow downstream of a pipe sudden expansion

Using the standard k-e turbulence model, an incompressible, axisymmetric turbulent flow with a sudden expansion was simulated. Effect of Prandtl number on heat transfer characteristics downstream of the expansion was investigated. The simulation revealed circulation downstream of the expansion. A secondary circulation (corner eddy) was also predicted. Reattachment was predicted at approximately 10 step heights. Corresponding to Prandtl number of 7.0, a peak Nusselt number 13 times the fully-developed value was predicted. The ratio of peak to fully-developed Nusselt number was shown to decrease with decreasing Prandtl number. Location of maximum Nusselt number was insensitive to Prandtl number.

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Flow structure at different stages of heat transfer deterioration with upward, mixed turbulent flow of supercritical CO2 heated in vertical straight tube

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2020.115987 ◽

2020 ◽

Vol 181 ◽

pp. 115987

Author(s):

Xinxin Liu ◽

Xiaoxiao Xu ◽

Chao Liu ◽

Shijie Zhang ◽

Jiacheng He ◽

...

Keyword(s):

Heat Transfer ◽

Turbulent Flow ◽

Flow Structure ◽

Supercritical Co2 ◽

Straight Tube ◽

Heat Transfer Deterioration

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Turbulent flow structure and heat transfer in an inclined bubbly flow. Experimental and numerical investigation

Fluid Dynamics ◽

10.1134/s0015462817010112 ◽

2017 ◽

Vol 52 (1) ◽

pp. 115-127 ◽

Cited By ~ 5

Author(s):

A. E. Gorelikova ◽

O. N. Kashinskii ◽

M. A. Pakhomov ◽

V. V. Randin ◽

V. I. Terekhov ◽

...

Keyword(s):

Heat Transfer ◽

Turbulent Flow ◽

Numerical Investigation ◽

Flow Structure ◽

Bubbly Flow ◽

Turbulent Flow Structure

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Experimental research of incipient turbulent flow frequency spectra in hydrodynamic unsteadiness

INCAS BULLETIN ◽

10.13111/2066-8201.2021.13.2.10 ◽

2021 ◽

Vol 13 (2) ◽

pp. 91-102

Author(s):

Viacheslav KRAEV

Keyword(s):

Heat Transfer ◽

Turbulent Flow ◽

Flow Structure ◽

Experimental Research ◽

Gas Flow ◽

Frequency Spectra ◽

Flow Acceleration ◽

Aerospace Systems ◽

Acceleration And Deceleration ◽

Unsteady Conditions

Hydraulic and heat transfer processes play a very important role in the design and prototyping of aerospace technology. Unsteady conditions are the peculiarity of mostly aerospace systems. Flow acceleration and deceleration may significantly affect the heat transfer and hydrodynamic process in channels of aerospace systems. For unsteady process modeling, a fundamental research of unsteady hydrodynamic turbulent flow structure., Moscow Aviation Institute National Research University (MAI) has been building unsteady turbulent flow structures since 1989. An experimental facility was designed to provide gas flow acceleration and deceleration. Experimental data of a turbulent gas flow structure during flow acceleration and flow deceleration are presented. The frequency spectra of axial and radial velocity pulsations are based on experimental data. The results of experimental turbulent flow research demonstrate the fundamental hydrodynamic unsteadiness influence on the flow structure. The main results of the flow acceleration and deceleration experimental research show that there are tangible differences from the steady flow structure. The analysis of unsteady conditions influence on the turbulent pulsations generation and development mechanisms is presented. The results show the unsteady conditions influence onto turbulent vortexes disintegration tempo. The present paper describes a method of experimental research, methodology of data processing and turbulent accelerated and decelerated flow spectra results.

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