Accurate estimation of mixing time in a direct contact boiling heat transfer process using statistical methods

Xu, Jianxin; Xiao, Qingtai; Yu, Fei; Wang, Shibo; Huang, Junwei

doi:10.1016/j.icheatmasstransfer.2016.04.012

Cited by 14 publications

(5 citation statements)

References 15 publications

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“…Xu et al. 24 presented a novel technique based on statistics and image processing for estimating mixing times during direct contact heat transfer. In order to determine the influence of quasi‐uniform time critical point on measurement results, the estimation of mixing time was studied by using the 3 σ method, and compared with the mean method, slope method, and standard deviation method by correlation degree and correlation coefficient analysis.…”

Section: Bubble Droplet Populations Of Direct Contact Evaporation Hea...mentioning

confidence: 99%

Research Progress on Direct Contact Evaporation Heat Transfer between Two Immiscible Working Fluids

Fu,

Xiong,

Liu

et al. 2023

Chem Eng & Technol

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The direct contact evaporation heat transfer of two immiscible fluids can realize low‐temperature differential heat transfer, which is an important method to improve the heat transfer coefficient. This article focuses on the dispersed phase of organic working fluids and the continuous phase of immiscible inorganic fluids and summarizes the research on direct contact evaporation heat transfer in the past 15 years. The main research methods include theoretical analysis, numerical models, and experimental research. The evaporation process of a single droplet mainly involves bubble droplet growth, droplet configuration and discriminant, droplet shape change, rising speed and path, etc. In practice, dispersed phases mostly exist in populations, and the research mainly focuses on collisions, coalescence, and rupture between droplets and bubbles, as well as on the number and size distribution. The volumetric heat transfer coefficient is used to reflect the heat transfer capacity of the heat exchanger. The factors affecting evaporation heat transfer performance are complex, and increasing the uniform mixing of bubbles is an important method to improve the heat transfer coefficient. In the future, direct contact evaporation heat transfer is expected to be promoted to multiple fields.

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Section: Bubble Droplet Populations Of Direct Contact Evaporation Hea...mentioning

confidence: 99%

Research Progress on Direct Contact Evaporation Heat Transfer between Two Immiscible Working Fluids

Fu,

Xiong,

Liu

et al. 2023

Chem Eng & Technol

View full text Add to dashboard Cite

show abstract

“…In algebraic topology, the zeroth Betti number β 0 equals the number of connected components that make up the space and the first Betti number β 1 provides a measure of the number of tunnels in the structure [38]. The Betti numbers are commonly used to characterize the homogeneity and inhomogeneity of multiphase mixing [3].…”

Section: Topological and Statistical Measures For Validationmentioning

confidence: 99%

“…There is however no universally accepted method for this issue mainly because each method has its own limitations. Recently, the three-sigma (3σ) method relying on image analysis and statistics was developed to estimate the mixing time accurately [38]. In the paper, we adopt this approach to estimate the mixing time accurately.…”

Section: Assessment Of Synergy Associationmentioning

confidence: 99%

Extraction and evolution of bubbles attributes in a two-phase direct contact evaporator

Xiao

Gao

Zhang

et al. 2018

International Journal of Heat and Mass Transfer

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Understanding the bubble regimes is a fundamental step toward conducting heat transfer enhancement. The non-invasive measurement of mixing inside a direct-contact heat transfer process, using a direct video imaging technology, provides powerful opportunities for characterising the visual observations of the phenomena and quantifying the process complexities previously. Experimental bubble shape feature parameters were obtained by means of the photographic recording technique for a direct-contact evaporator. Four design factors with three levels respectively were analysed for the mixing system that involves the exchange of heat between two immiscible fluids (continuous and dispersed phases). Using the Ripley's K function, new results are presented for two-phase flow mixing which can distinguish differences in the mixing behavior of dispersed phase. In all cases considered, quantitative comparisons of the evolution curves representing different experimental conditions were conducted with reported experimental data. Following the local mixing curve, the current results can also be processed to provide the mixing time found to be in good agreement with available data. The relationship between shape feature parameters of bubbles and volumetric heat transfer coefficient was found to be highly independent on experimental design parameters.

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“…The heat transfer between the phases takes place at the interface. Therefore the knowledge of heat transfer enhancement is fundamental for the design and operation of DCHE [2].…”

Section: Introductionmentioning

confidence: 99%

“…Xu et al (2011) also applied computational algebraic topology and image analysis to quantify the mixture homogeneity and non-homogeneity in gas agitated rectors stirred by top lance gas injection [20]. The critical point determination of pseudo homogeneous process impact on the accurate estimation of mixing time could be investigated by three-sigma (3σ) method [2]. Fei et al (2015) and addressed the key issue that how to measure the spacetime uniformity of random bubble swarm in a domain with minimum discrepancy [6,21].…”

Section: Introductionmentioning

confidence: 99%

Measure of bubble non-uniformity within circular region in a direct-contact heat exchanger

Xiao

Pan

et al. 2017

International Journal of Heat and Mass Transfer

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The study of bubble swarm distributions in a direct-contact heat exchanger was addressed both theoretically and experimentally. But recently developed approach based on uniform design for measuring bubbles uniformity and mixing efficiency within rectangular or square region can not be used to characterise the mixture homogeneity and mixing time within circular region. This paper discussed the difference between rectangular or square region and circular region. A quantitative metric of mixing uniformity is used to characterize the bubble patterns within circular region. Simulation studies are also used to illustrate the proposed methodologies while the experimental case considered demonstrate that the proposed approach evaluated the experimental data rather well. The space-time features of the mixing transient have been successfully derived when the bubble swarms or other objects distribute in a circular region. This work brings new insights to evaluate mixing quality of different systems practically, which has a high degree of accuracy (the percentage of enhancing achieved is about 40%).

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Accurate estimation of mixing time in a direct contact boiling heat transfer process using statistical methods

Cited by 14 publications

References 15 publications

Research Progress on Direct Contact Evaporation Heat Transfer between Two Immiscible Working Fluids

Research Progress on Direct Contact Evaporation Heat Transfer between Two Immiscible Working Fluids

Extraction and evolution of bubbles attributes in a two-phase direct contact evaporator

Measure of bubble non-uniformity within circular region in a direct-contact heat exchanger

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