The characteristics of boiling heat transfer and pressure drop of R-600a in a circular tube with porous inserts

Wen, Mao-Yu; Jang, Kuang-Jang; Ho, Ching-Yen

doi:10.1016/j.applthermaleng.2013.12.074

Cited by 36 publications

(9 citation statements)

References 31 publications

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“…R600a is considered as one of the most environmentally friendly refrigerants [24,25]. POE with a commercial name of RL68H is applied as the lubricant added to the pure refrigerant by 1% mass fraction to form the baseline mixture.…”

Section: B Working Fluidsmentioning

confidence: 99%

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Akhavan-Behabadi

Sadoughi

Darzi

et al. 2017

Journal of Thermophysics and Heat Transfer

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An empirical investigation is performed on boiling heat transfer characteristics of R600a refrigerant flow inside horizontal flattened tubes. Round copper tubes of 8.7 mm inner diameter are deformed into flattened shapes with different internal heights of 6.9, 5.5, and 3.4 mm as the test sections. Effects of different parameters such as mass flux, vapor quality, and internal tube height on the heat transfer coefficient are studied. It is shown that flattening the tube causes significant heat transfer enhancement. The maximum augmentation ratio of 163% is obtained for the flattened tube with the maximum aspect ratio of 3.56. A new correlation is developed based on the obtained experimental data to predict the heat transfer coefficient in flattened tubes; 90% of the acquired data are predicted within. Consequently, the tested flattened tube with maximum heat transfer rate is selected to study the effects of nanoparticles. Experiments are conducted for three different working fluid types including 1) pure refrigerant (R600a); 2) refrigerant/lubricant (R600a/oil); and 3) nanorefrigerant: refrigerant/lubricant/nanoparticles (R600a/oil/CuO). Polyolester oil is used as the lubricant in the two latter cases. In addition, nanorefrigerants (R600a/oil/CuO) are prepared by dispersing CuO nanoparticles with different mass fractions of 0.5, 1, and 1.5% in the baseline mixture (R600a/oil). Thereby, maximum heat transfer enhancement of 79% is achieved compared to the pure refrigerant case. The results of this study provide the platform for designing compact efficient heat exchangers/heat sinks for the emerging thermal engineering applications under high thermal load conditions. NomenclatureA = area, m 2 D = diameter, m D e = equivalent diameter, m D h = hydraulic diameter, m G = mass flux, kg∕m 2 · s H = channel height, m e = enthalpy, J∕kg h = heat transfer coefficient, kW∕m 2 · K K = thermal conductivity, kW∕m 2 · K L = length, m m = mass flow rate, kg∕s Q pre = preheater heat transfer rate, W Q test = evaporator heat transfer rate, W W = channel width, m x = quality ω = mass fraction Subscripts f = flat in = inlet l = liquid loc = local concentration no = nominal concentration o = oil out = outlet R = refrigerant s = surface Th = thermocouple v = vapor wall = tube wall

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Section: B Working Fluidsmentioning

confidence: 99%

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Akhavan-Behabadi

Sadoughi

Darzi

et al. 2017

Journal of Thermophysics and Heat Transfer

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“…Three porous-coated rectangular micro-channel samples (named as #1, #2 and #3) and a bare micro-channel sample (named as #0) were prepared using EDM wire cutting process and solid state technology was used for employing a metallic porous coating in the bottom of the microchannels. Wen et al [57] studied two phase pressure drop characteristics of R-600a (iso-butane) in a tube having dispersed-copper porous inserts. 3.11.…”

Section: Mitigating Pressure Drop Oscillationsmentioning

confidence: 99%

Heat Transfer and Pressure Drop in Flow Boiling in Microchannels

Saha¹,

Celata²

2016

SpringerBriefs in Applied Sciences and Technology

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“…Wen et al [14] investigated the boiling heat transfer and pressure drop characteristic of R-600a in a circular tube with porous inserts. Their test was conducted at the saturation temperature of 10°C, vapor qualities up to 0.87, mass velocities of 120-1100 kg/m 2 s and heat fluxes from 12 to 65 kW/m 2 .…”

Section: Introductionmentioning

confidence: 99%

Heat transfer characteristic of R-600a during flow boiling inside horizontal plain tube

Nasr

Akhavan-Behabadi

Momenifar

et al. 2015

International Communications in Heat and Mass Transfer

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The characteristics of boiling heat transfer and pressure drop of R-600a in a circular tube with porous inserts

Cited by 36 publications

References 31 publications

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Heat Transfer and Pressure Drop in Flow Boiling in Microchannels

Heat transfer characteristic of R-600a during flow boiling inside horizontal plain tube

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