Evaporation heat transfer and pressure drop of ammonia in a mixed configuration chevron plate heat exchanger

Khan, M. Adam; Khan, Tariq S.; Chyu, M.-C.; Ayub, Zahid H.

doi:10.1016/j.ijrefrig.2013.12.015

Cited by 37 publications

(33 citation statements)

References 11 publications

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“…Secondly, the enhancement of the heat transfer coefficient becomes minimal at the low qualities, where isolated/coalescing bubbly regimes are expected, and the values converge approximately on the same magnitude attributed to the onset of boiling. Similar results were also reported in Yan and Lin (1999), Hsieh and Lin (2002), Hsieh and Lin (2003), Djordjevic and Kabelac (2008), and Khan et al (2014).…”

Section: Resultssupporting

confidence: 90%

Two-Phase Flow of R245fa in a 1mm Corrugation Depth Plate Heat Exchanger - Part Ii: Flow Boiling Heat Transfer

Vakili-Farahani

Amalfi

Thome

2014

Interfac Phenom Heat Transfer

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This article is the second in a two-part study on two-phase flow of R245fa in a new promising and more compact plate heat exchanger (PHE). Two-phase adiabatic frictional pressure drops were detailed in Part I, while the flow boiling heat transfer coefficients were obtained and the results presented here in Part II. Upward flow boiling heat transfer was investigated locally within the PHE prototype using an IR camera to measure the local PHE wall temperatures with high resolution. A new experimental approach for PHEs was introduced in order to reduce the data and obtain the local pixelby-pixel flow boiling heat transfer coefficients throughout the PHE. The influences of heat flux, mass flux, saturation temperature, vapor quality, and inlet condition on flow boiling heat transfer coefficients were obtainable. During the tests, the vapor qualities changed from 0 to 0.78 for mass fluxes from 7.5 to 40 kg m −2 s −1 , heat fluxes from 250 to 3700 W m −2 , and saturation temperatures from 19 • C to 35 • C. In addition, comparative flow boiling experiments were carried out with a small subcooling and then repeated with liquid-vapor (xin ≈ 0.1-0.2) flow at the PHE inlet. Several of the most widely used prediction methods in the PHE literature were evaluated with respect to the current mean and quasi-local (obtained in six windows) experimental databases. The prediction methods mostly showed a better agreement with the mean flow boiling heat transfer coefficients rather than the local database.KEY WORDS: two-phase flow, plate heat exchanger, flow boiling heat transfer, pressure drop, R245fa

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Section: Resultssupporting

confidence: 90%

Two-Phase Flow of R245fa in a 1mm Corrugation Depth Plate Heat Exchanger - Part Ii: Flow Boiling Heat Transfer

Vakili-Farahani

Amalfi

Thome

2014

Interfac Phenom Heat Transfer

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“…Unlike the experimental results in Refs. [8][9][10][11][12], a nucleate boiling-dominant process was found by Huang et al [13] when outlet vapour quality xout = 0.4-1. The authors performed an experimental investigation of the heat transfer and pressure drop of R134a and R507A with three industrial PHEs.…”

Section: Symbols Subscriptsmentioning

confidence: 84%

“…In the flow boiling process, two main heat transfer mechanisms exist, which are named nucleate and convective boiling. A common phenomenon has been presented in some research [8][9][10][11][12], that is, nucleate boiling and convective boiling are predominant at low and high vapour qualities, respectively. With the further increase of vapour quality, the flow enters into the dryout regime.…”

Section: Symbols Subscriptsmentioning

confidence: 92%

Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

Zhang

Desideri

Kærn

et al. 2017

International Journal of Heat and Mass Transfer

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“…However, Khan et al (2014) reported that the increase of chevron angle β leads to enhancement in heat transfer coefficient in flow boiling, similar as in single-phase flow. Unexpectedly the most influence of the chevron angle β appears in power at reduced pressure P R which is changing from 0.198 at β = 60° to 0.51 at β = 30°.…”

Section: Nu Bnmentioning

confidence: 97%

- Introduction

2015

Compact Heat Exchangers for Energy Transfer Intensification

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Evaporation heat transfer and pressure drop of ammonia in a mixed configuration chevron plate heat exchanger

Cited by 37 publications

References 11 publications

Two-Phase Flow of R245fa in a 1mm Corrugation Depth Plate Heat Exchanger - Part Ii: Flow Boiling Heat Transfer

Two-Phase Flow of R245fa in a 1mm Corrugation Depth Plate Heat Exchanger - Part Ii: Flow Boiling Heat Transfer

Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

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