Heat transfer during condensation of refrigerants in tubular minichannels

Bohdal, T.; Charun, H.; Sikora, Małgorzata

doi:10.2478/v10173-012-0008-x

Cited by 21 publications

(21 citation statements)

References 32 publications

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“…Static and dynamic disturbances may upset the structure of the distribution of heat transfer regions. This includes a reduction of the active region of condensation, where the heat transfer coefficient reaches its highest value, as reported by Bohdal et al [34].…”

Section: Introductionmentioning

confidence: 55%

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Kuczyński

Charun

2013

Heat Transfer Engineering

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The heat removal process of a compact condenser in a refrigeration compressor system, constructed on the basis of pipe minichannels, occurs in three regions: the removal region of superheat, the two-phase proper condensation region, and the liquid subcooling region. The intensity of heat removal in the two-phase region depends on the heat efficiency of the condenser. The length of this region is determined by the process parameters and the external influences. This paper analyzes the influence of periodically generated hydrodynamic disturbances on the length of the condensation region for R134a and R404A refrigerants. Experimental tests were conducted for six diameters of pipe minichannels: 0. 64, 0.90, 1.44, 1.92, 2.30, and 3.30 mm. A range of frequencies from 0.2 to 5 Hz of periodically generated disturbances showed an explicit and unfavorable influence on the decrease of the length of the proper condensation region. This influence reduced the efficiency of the process. A computational model was developed to calculate the length of the two-phase region under disturbance conditions. The model proposed was verified by the results of the experiment, and compliance was obtained in the range of ±15%.

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Section: Introductionmentioning

confidence: 55%

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Kuczyński

Charun

2013

Heat Transfer Engineering

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“…We can evaluate the integral given in Equation (11) or any by using Schwinger's trick to turn the integrand into a Gaussian (see Figure 1):…”

Section: Applications Of the Green Functionalmentioning

confidence: 99%

“…The selected elementary section PAQB can be divided into four linear sections, called PB, AQ, BQ and AP. For any of these linear sections, the solution of the differential equation (12) and its combination with the integral criterion of Green, allows obtaining an integral complex, which allows solving the problem on the studied boundary at any point inside and outside the volume of control, [10][11]:…”

Section: Figure 2 Model Problem and Elementary Volumes Employedmentioning

confidence: 99%

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Suggested Method for Heat Transfer Calculation During Film Condensation Inside Pipes with Movable Frontiers

Camaraza-Medina¹,

García-Lovella²,

Sánchez-Escalona³

et al. 2019

MMEP

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This paper provides a second evaluation, with the intention of formulating an improved model that is capable of predicting the mean coefficients of heat transfer during condensation inside tubes with any orientation. This model has been developed through the application of transportable borders for the propagation of heat inside an elementary volume, up to the macro system considered. The theoretical model obtained leads to two basic dimensionless groups, which establish the study intervals that should be considered in the correlation of experimental quantities available, for the development of future experimental models.

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“…The measure of the effectiveness of this intensification is increase of the heat transfer coefficient. It can be said that the construction of modern refrigeration and air conditioning heat exchangers should meet the technical and environmental criteria, like: compact dimensions, high heat transfer efficiency, and minimal impact on the environment [3,4,13].…”

Section: Introductionmentioning

confidence: 99%

Condensation of refrigerant R407C in multiport minichannel section

Bohdal¹,

Charun²,

Sikora³

2016

Archives of Thermodynamics

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Analysis of the state of-the-art in research of refrigerant condensation in miniature heat exchangers, so-called multiports, was made. Results of refrigerant R407C condensation in a mini condenser made in the form of two bundles of tubular minichannels from stainless steel with an inside diameter 0.64 mm and length 100 mm have been presented. Two exchangers consisted of four minichannels and 8 minichannels have been investigated. The values of average heat transfer coefficient and frictional pressure drops throughout the condensation process were designated. The impact of the vapor quality of refrigerant and the mass flux density on the intensity of heat transfer and flow resistance were illustrated. A comparative analysis of test results for various refrigerants in both mini heat exchangers were made.

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Heat transfer during condensation of refrigerants in tubular minichannels

Cited by 21 publications

References 32 publications

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Suggested Method for Heat Transfer Calculation During Film Condensation Inside Pipes with Movable Frontiers

Condensation of refrigerant R407C in multiport minichannel section

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