Experimental observations of thermal mixing characteristics in T-junction piping

Chen, Mei-Shiue; Hsieh, Hsin‐Ju; Ferng, Yuh-Ming; Pei, Bau-Shei

doi:10.1016/j.nucengdes.2014.03.052

Cited by 24 publications

(11 citation statements)

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“…Many experimental [7][8][9], numerical [10][11][12][13], and combinations of both [14][15][16][17] research have been conducted by many researchers all over the world to investigate the thermal mixing characteristics and mixing performance of T-junction. There are some identified factors such as Tjunction's geometry, inclination angle between a branch and main pipe, diameter ratio, inlet temperature difference, velocity ratio, mass flow rate, etc.…”

Section: Introductionmentioning

confidence: 99%

“…Inlet temperature difference is a function of temperature fluctuation and thermal mixing quality. If the temperature difference is lower, the thermal mixing quality will be higher, and mixing performance decreases with the increase of inlet fluid temperature difference [7,20]. Chen et al, [7] found that the influence of branch and main pipe inlet flow rate ratio on thermal mixing quality experimentally and concluded that if the flow rate ratio is getter than 0.16, then the thermal mixing quality will be good.…”

Section: Introductionmentioning

confidence: 99%

“…The thermal mixing performance is therefore proportional to the flow rate ratio [21][22][23][24][25]. Mixing quality increases with the increase of branch to main pipe velocity ratio [7]. If the velocity ratio is more than 13.6, then the mixing quality will be good.…”

Section: Introductionmentioning

confidence: 99%

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Simulation Analysis of Thermal Mixing Characteristics of Fluids Flowing Through a Converging T-junction

Nuruzzaman

Pao

et al. 2021

CFDL

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Temperature fluctuation occurs while mixing of hot and cold fluids in a T-junction due to incomplete thermal mixing. This temperature fluctuation can produce thermal fatigue at the weld area of the T-junction. The present study aims to numerically investigate the thermal mixing characteristics of hot and cold fluids in a T-junction. The realizable k-ε turbulence model is used with natural gas as the working fluid. Temperature distribution, mixing quality, and intensity of temperature fluctuation are evaluated and compared along with the mixing outlet. The inlet temperature difference and branch to main pipe flowrate ratio have a direct influence on thermal mixing. The higher temperature difference can reduce the thermal mixing performance. Thermal mixing increases with the increase of branch to main pipe flowrate. The intensity of temperature fluctuation is found within a short distance from the intersecting point of the two inlets. With the increase of distance along with the mixing outlet, the frequency of temperature fluctuation decreases, and thermal mixing increases.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simulation Analysis of Thermal Mixing Characteristics of Fluids Flowing Through a Converging T-junction

Nuruzzaman

Pao

et al. 2021

CFDL

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“…They reported that the thermal mixing for a T-junction could be enhanced as the flow rate in the branch increases or the flow rate in the main pipe decreases, as clearly revealed in the comparison results of different flow rate ratios. A small-scaled test facility to investigate the mixing effects in a T-junction with two streams at different temperatures and flow rates in the main and branch pipes preliminarily was devised by Chen et al [13], who found that a lower main pipe flow rate led to a better mixing effect with a constant branch pipe flow rate. The T-junction with a 90 • bend upstream mixing phenomenon experimentally was reviewed by Hosseini et al [14].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study of Turbulent Mixing Characteristics in a T-Junction System

et al. 2020

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The mixing, migration, and degradation of pollutants in sewers are the main causes for pipeline corrosion and the increased pollution scope. The clarification of the turbulent mixing characteristics in pipelines is critical for finding the source of pollution in a timely fashion and inspecting pipelines’ damaged locations. In this paper, numerical simulations and experiments were conducted to investigate the turbulent mixing characteristics in pipelines by studying a T-junction system, of which four variables (main pipe diameter φ, cross-flow flux Q, mixing ratio δ, the incident angle of T-junctions θ) were considered. The coefficient of variation (COV) of the salt solution was selected as the evaluation index and effective mixing length (LEML) was defined for quantitative analysis. The numerical results were found to be in good agreement with the experimental results. The results reveal that the values of LEML rise as Q or φ increase and decrease with the increase of δ, where the influence of φ is much greater than Q and δ, and there is no obvious regularity between LEML and θ. By dimensional analysis and multivariate nonlinear regression analysis, a dimensionless relationship equation in harmony with the dimensional analysis was fitted, and a simplified equation with the average error of 4.01% was obtained on the basis of correlation analysis.

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“…This most quickly occurs at high values of the amplitude and number of loading cycles (Wakamatsu et al 1995, Beaufils 2011, Courtin 2013. However, in the domestic and foreign literature there are no comprehensive experimental data on a single-phase coolant mixing at temperature drops of more than 100 °С (Miyoshi et al 2016, Braillard and Edelin 2009, Chen et al 2014, Kamide et al 2009). Therefore, it was an important task to develop an experimental section for simulating the process of mixing coolant flows accompanied by significant temperature pulsations.…”

Section: Introductionmentioning

confidence: 99%

Experimental studies of temperature pulsations during the process of mixing non¬isothermal coolant flows in nuclear reactor equipment components

Dmitriev

Мамаев

Rayzapov

et al. 2019

YadEn

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One of the most important scientific and technical tasks of the nuclear power industry is to assure the reactor equipment life and reliability under random temperature pulsations. High-intensity temperature pulsations appear during the process of mixing non-isothermal coolant flows. Coolant thermal pulsations cause corresponding, sometimes very significant, fluctuations in the temperature stresses of the heat-exchange surface metal, which, added to static loads, can lead to fatigue failure of equipment components. The purpose of this work was to conduct an experimental study of the temperature and stress-strain states of a pipe sample under the influence of local stochastic thermal pulsations caused by the mixed single-phase heat coolant flows. To solve the set problems, an experimental section was created, which made it possible to simulate the process of mixing non-isothermal coolant flows accompanied by significant temperature pulsations. The design of the experimental section allowed us to study the thermohydraulic and life characteristics of pipe samples made of austenite steel (60×5 mm). Some tools were developed for measuring the pipe sample stress-strain state and the coolant flow temperature field in the zone of mixed single-phase media with different temperatures. The measuring tools were equipped with microthermocouples and strain sensors. As a result, we obtained experimental data on temperature pulsations, time-averaged temperature profiles of the coolant flow in the mixing zone as well as statistical and spectral-correlation characteristics of thermal pulsations. Based on the results of measuring the relative strains, the values of fatigue stresses in the mixing zone were calculated. In addition, some devices and methods were elaborated to measure the temperature and stress-strain states of the pipe sample under the influence of local stochastic thermal pulsations. The developed experimental section provided thermal-stress loading of the metal surface at a high level of alternating stress amplitudes causing rapid damage accumulation rates. The results were included in the database to verify the method for assessing the fatigue life of structural materials for nuclear power plants as applied to austenite steel 12Cr18Ni10Ti under the influence of random thermal cyclic loads.

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Experimental observations of thermal mixing characteristics in T-junction piping

Cited by 24 publications

References 1 publication

Simulation Analysis of Thermal Mixing Characteristics of Fluids Flowing Through a Converging T-junction

Simulation Analysis of Thermal Mixing Characteristics of Fluids Flowing Through a Converging T-junction

Numerical and Experimental Study of Turbulent Mixing Characteristics in a T-Junction System

Experimental studies of temperature pulsations during the process of mixing non¬isothermal coolant flows in nuclear reactor equipment components

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