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Air-side heat transfer and pressure drop of the fin-and-tube heat exchangers having oval tubes under wet condition

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Abstract

It is well known that the replacement of a round tubes to an oval tube in a fin-and-tube heat exchanger reduces an air-side pressure drop as well as a low performance region behind the tube, and improves the thermal performance of the heat exchanger. However, experimental evidences are lacking, especially for generic heat exchangers. In this study, three generic samples with oval tubes were obtained and tested under wet condition. The samples had different oval tube dimensions and tube pitches. One interesting result was that the highest j factor was obtained at a two row configuration. Possible explanation was provided considering the effect of fin efficiency. The wet surface j factors were slightly lower and the wet f factors were significantly higher than those of the dry surface, probably due to the condensate on the fin surface. A thermal performance comparison (based on the conductance per unit volume (ηohoAo/Vo) to the pressure drop per unit length (ΔP/L)) revealed that, the oval tube samples yielded higher performances than the round tube samples with some exceptions at a large number of tube row. Furthermore, it was found that the oval tube geometry is more effective under wet condition than under dry condition. Correlations were developed, which predicted all the j factor and 98% of the f factor within ±20%.

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Abbreviations

A :

heat transfer area, m2

AR :

aspect ratio

a :

major diameter, m

b :

minor diameter [m] or slope of enthalpy-temperature curve of saturated air, kJ/kgK

C :

heat capacity ratio

c p :

specific heat, J/kg s

D c :

tube diameter including fin collar thickness, m

D min :

minimum tube diameter, m

EI :

efficiency index

f :

friction factor

h :

heat transfer coefficient, W/m2K

j :

Colburn j factor

k :

thermal conductivity, W/m K

L :

heat exchanger length, m

\( \dot{m} \) :

mass flow rate, kg/s

N :

number of tube row

NTU :

number of transfer units

p :

ratio of outer and inner diameter

P d :

fin depth, peak to valley excluding fin thickness, m

P f :

fin pitch, m

P t :

transverse tube pitch, m

P l :

longitudinal tube pitch, m

Pr :

Prandtl number

q :

ratio of major and minor diameter

r c :

tube radius including fin collar, m

R eq :

equivalent radius, m

ReDc :

Reynolds number based on Dc

ReDmin :

Reynolds number based on Dmin

RH :

relative humidity

t :

tube wall thickness, m

t f :

fin thickness, m

U :

overall heat transfer coefficient, W/m2K

V :

velocity, m/s

V o :

volume, m3

x f :

wave pitch, m

ΔP :

pressure loss, Pa

η :

fin efficiency

η o :

surface efficiency

θ :

corrugation angle, degree

ρ :

density, kg/m3

σ :

contraction ratio of the cross-sectional area

ξ :

thermal performance index

a :

air

h :

hydraulic

i :

tubeside

in :

inlet

f :

fin

m :

mean

max :

maximum

min :

minimum

o :

airside

out :

outlet

r :

tube-side

t :

tube wall

w :

water

References

  1. Mirth DR, Ramadhyani S (1993) Prediction of cooling coil performance under condensing conditions. Int J Heat Fluid Flow 14:391–400

    Article  Google Scholar 

  2. Wang C-C, Liaw J-S, Yang B-C (2011) Airside performance of herringbone wavy fin-and-tube heat exchangers – data with larger diameter tube. Int J Heat Mass Trans 54:1024–1029

    Article  Google Scholar 

  3. Liu Y-C, Wongwises S, Chang W-J, Wang C-C (2010) Airside performance of fin-and-tube heat exchangers in dehumidifying conditions – data with larger diameter. Int J Heat Mass Trans 53:1603–1608

    Article  Google Scholar 

  4. Min J-C, Webb RL (2004) Numerical analyses of effects of tube shape on performance of a finned tube heat exchanger. J Enhanced Heat Trans 11:61–73

    Article  Google Scholar 

  5. Leu J-S, Liu M-S, Liaw J-S, Wang C-C (2001) A numerical investigation of louvered fin-and-tube heat exchangers having circular and oval tube configurations. Int J Heat Mass Trans 44:4235–4243

    Article  Google Scholar 

  6. Han H, He Y-L, Li Y-S, Wang Y, Wu M (2013) A numerical study on compact enhanced fin-and-tube heat exchangers with oval and circular tube configurations. Int J Heat Mass Trans 65:686–695

    Article  Google Scholar 

  7. Tao Y-B, He Y-L, Wu Z-G, Tao W-Q (2007) Three-dimensional numerical study and field synergy principle analysis of wavy fin heat exchangers with elliptic tubes. Int J Heat Fluid Flow 28:1531–1544

    Article  Google Scholar 

  8. Gholami A, Wahid MA, Mohammed HA (2017) Thermal hydraulic performance of fin-and-oval tube compact heat exchangers with innovative design of corrugated fin patterns. Int J Heat Mass Trans 106:573–592

    Article  Google Scholar 

  9. Gholami A, Mohammed HA, Wahid MA, Khiadani M (2019) Parametric design exploration of fin-and-oval tube compact heat exchanger performance with a new type of corrugated fin patterns. Int J Thermal Sci 144:173–190

    Article  Google Scholar 

  10. Saboya SM, Saboya FEM (2001) Experiments on elliptic sections in one- and two-row arrangements of plate fin and tube heat exchangers. Exp Thermal Fluid Sci 24:65–75

    Article  Google Scholar 

  11. Matos RS, Laursen TA, Vargas JVC, Bejan A (2004) Three-dimensional optimization of staggered finned circular and elliptic tubes in forced convection. Int J Thermal Sci 43:477–487

    Article  Google Scholar 

  12. Chu W-X, Sheu W-J, Hsu C-C, Wang C-C (2020) Airside performance of sinusoidal wavy fin-and-tube heat exchangers subject to large diameter tubes with round or oval configuration. Appl Therm Eng 164:114469

    Article  Google Scholar 

  13. Myung J-H, Choi B-N, Go M-G, Kim N-H (2020) Experimental investigation on airside heat transfer and pressure drop of fin-and-tube heat exchangers having oval tubes. Submitted to Exp. Heat Trans

    Google Scholar 

  14. ASHRAE Standard 41.1 (1986) Standard method for temperature measurement. ASHRAE, Atlanta

  15. ASHRAE Standard 41.2 (1987) Standard method for laboratory air-flow measurement. ASHRAE, Atlanta

  16. ASHRAE Standard 41.5 (1975) Standard measurement guide, engineering analysis and experimental data. ASHRAE, Atlanta

  17. Kim N-H, Lee K-J, Jeong Y-B (2014) Airside performance of oval tube heat exchangers having sine wave fins under wet condition. Appl Therm Eng 66:580–589

    Article  Google Scholar 

  18. ESDU 98005 (1998) Design and performance evaluation of heat exchangers: the effectiveness and NTU method, Engineering and Sciences Data Unit 98005 with Amendment A, London ESDU International plc, pp 122–129

    Google Scholar 

  19. Mills AF (1999) Basic heat and mass transfer, 2nd edn. Prentice-Hall, Upper Saddle River

  20. Gnielinski V (1976) New equations for heat and mass transfer in turbulent pipe flows. Int Chem Eng 16:359–368

    Google Scholar 

  21. Min J-C, Tao T, Peng X-F (2003) Efficiency of fins used in a finned oval tube heat exchanger. J Enhanced Heat Trans 10:323–334

    Article  Google Scholar 

  22. Schmidt TE (1949) Heat transfer calculations for extended surfaces. J ASRE Refrig Eng 4:351–357

    Google Scholar 

  23. Torikoshi K, Xi G-N, Nakazawa Y, Asano H (1994) Flow and heat transfer performance of a plate fin and tube heat exchanger (first report: effect of fin pitch). 10th Int Heat Transfer Conf 4:411–416

    Article  Google Scholar 

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  1. Department of Mechanical Engineering, Incheon National University, 12-1, Songdo-Dong, Yeonsu-Gu, Incheon, 406-772, Republic of Korea

    Nae-Hyun Kim

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Kim, NH. Air-side heat transfer and pressure drop of the fin-and-tube heat exchangers having oval tubes under wet condition. Heat Mass Transfer 57, 1633–1644 (2021). https://doi.org/10.1007/s00231-021-03058-1

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