Header design tradeoffs in microchannel evaporators

Kulkarni, T.; Bullard, Clark W.; Cho, Keumnam

doi:10.1016/j.applthermaleng.2003.10.016

Cited by 77 publications

(16 citation statements)

References 10 publications

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“…Otherwise, the thermal performance is significantly deteriorated. According to Kulkarni et al [1], the performance reduction by flow mal-distribution could be as large as 20%. The most of the studies on two-phase distribution in a header-branch configuration have been conducted on a single pass configuration [ Fig.…”

Section: Introductionmentioning

confidence: 99%

Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

Byun

Kim

2015

Heat Mass Transfer

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Brazed aluminum heat exchangers are recently considered as evaporators of automotive or residential air conditioners. In this case, it is very important to distribute the two-phase refrigerant (especially the liquid) evenly into each tube. In this study, R-410A distribution in a two pass evaporator with upper horizontal combining-dividing header was investigated. Tubes were heated to yield a test section outlet superheat of 5 o C with inlet quality of 0.2. The number of tubes was 10 for the inlet pass and 12 or 14 for the outlet pass. For each case, mass flux was varied from 73 kg/m 2 s to 143 kg/m 2 s. In the combining/dividing header, two-phase mixture out of the inlet pass is first merged and then re-distributed to the outlet pass. More liquid is forced downstream as mass flux or quality increases yielding better flow distribution. Effect of insertion device in the inlet header was also investigated. Efforts were made to develop correlations to predict the liquid or gas distribution in a header with limited success. Header pressure drop data are also provided.

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Section: Introductionmentioning

confidence: 99%

Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

Byun

Kim

2015

Heat Mass Transfer

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“…As a consequence, the refrigerant distribution is much more penalizing for these exchangers than for round tube heat exchangers. Indeed, according to Kulkarni et al [2], an uneven distribution may result in a performance reduction up to 20 %.…”

Section: Introductionmentioning

confidence: 99%

Infrared Thermography applied to measurement of Heat transfer coefficient of water in a pipe heated by Joule effect

Leblay¹,

Henry²,

Caron³

et al. 2012

Proceedings of the 2012 International Conference on Quantitative InfraRed Thermography

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A methodology has been developed based on periodic excitation by Joule effect and infrared thermography measurement. It has been applied to measure heat transfer coefficients of water flowing in a round tube and in a multiport-flat tube. Models were developed to deduce heat transfer coefficient from wall temperature amplitude and heat flux measurement. For the round tube and for the multiport flat tubes, Reynolds number investigated ranges respectively from 2000 to 14000 and from 800 to 10000 and heat flux from 5 W to 29 W and from 10 W to 70 W. The good agreement between experimental and theoretical results has demonstrated the reliability of the methodology. This methodology also present the advantage to require a low heat flux, is not intrusive and fluid independant.

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“…The none-uniform distribution of two phase refrigerant in evaporator can significantly deteriorate the heat exchanger performance as well as system efficiency. Many simulation results shows that the capacity degradation due to refrigerant maldistribution ranges from 5% to 23% (Kulkarni et al, 2004;Brix et al 2009Brix et al , 2010Zou et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Quantification of liquid refrigerant distribution in parallel flow microchannel heat exchanger using infrared thermography

Hrnjak

2015

Applied Thermal Engineering

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This paper presents a method to quantify the distribution of liquid refrigerant mass flow rate in parallel flow microchannel heat exchanger from the infrared images. Quantification is achieved by building the relationship between the liquid mass flow rate through each microchannel tube and the air side capacity calculated from the infrared measurement of the wall temperature. After being implemented in a heat exchanger model, the quantification method is validated against experimental data. This method can be used for several types of heat exchangers: evaporators, condensers etc., also it can be applied to various heat exchanger designs: different inlet/outlet locations, different flow configurations etc.

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Header design tradeoffs in microchannel evaporators

Cited by 77 publications

References 10 publications

Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

Infrared Thermography applied to measurement of Heat transfer coefficient of water in a pipe heated by Joule effect

Quantification of liquid refrigerant distribution in parallel flow microchannel heat exchanger using infrared thermography

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