Investigation on the thermal mixing enhancement in a T-junction pipe

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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“…The thermal mixing performance of hot and cold fluids can be defined by Temperature Mixing Degree (TMD). This TMD can be expressed as [35],…”

Section: Thermal Mixing Performancementioning

confidence: 99%

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

Nuruzzaman

Pao

et al. 2021

CFDL

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“…To find out thermal mixing performance of hot and cold fluids more accurately, it is required to calculate the Temperature Mixing Degree, TMD [32], defined as:…”

Section: Calculation Of Thermal Mixing Efficiencymentioning

confidence: 99%

A Preliminary Numerical Investigation of Thermal Mixing Efficiency in T-Junctions with Different Flow Configurations

Nuruzzaman¹,

Pao²,

Ejaz³

et al. 2021

IJHT

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When hot and cold fluids flow through a converging T-junction, rapid temperature fluctuations occur in the mixing region due to the thermal mixing of fluids. This temperature fluctuation causes thermal fatigue, which is responsible for the shortening of service life in a T-junction. Hence, the design of T-junction for thermal mixing requires not only superior mixing performance but minimize thermal fluctuation during mixing is also desirable. The objective of the present paper is to determine the thermal mixing performance at the mixing region of T-junction with two different flow configurations. Water, at different inlet temperatures, is used as a working medium and is assumed incompressible. Two types of flow configurations, namely intersecting and colliding regular T-junction with a sidearm pointing at 12 o’clock position have been evaluated in this paper. Realizable k-epsilon turbulence model was assumed, and its validity benchmarked against RANS and RSM-EB turbulence models. The thermal mixing efficiency of both flow configurations is calculated and compared. The results show that the thermal mixing efficiency of both intersecting and colliding mixing tee increases with the increase of distance and time. Intersecting tee shows higher temperature fluctuation than colliding tee at the mixing outlet, but colliding tee shows higher thermal mixing efficiency than intersecting mixing tee.

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“…Results showed that a 90 • bend had a strong effect on the fluid mixing mechanism and the momentum ratio between the main velocity and the branch velocity of the T-junction, which could be an important parameter for the classification of the fluid mixing mechanism. The thermal mixing of turbulent flow in a T-junction with hot fluid flowing in the main pipe and cold fluid in the branch by three-dimensional numerical simulations was investigated by Hekmat et al [15]. They concluded that the injection angles and flow rate ratios had significant influence on the reverse and secondary flow on the mixing.…”

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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Investigation on the thermal mixing enhancement in a T-junction pipe

Cited by 5 publications

References 30 publications

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

A Preliminary Numerical Investigation of Thermal Mixing Efficiency in T-Junctions with Different Flow Configurations

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

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