Advertisement

The single-blow transient test technique using pulse change inlet condition with optimized pulse width and matching time

  • Hai-Xia Wang
  • Guo-Yan ZhouEmail author
  • Xing Luo
  • Stephan Kabelac
  • Shan-Tung TuEmail author
Original
  • 10 Downloads

Abstract

Compact heat exchanger is a kind of advanced heat transfer equipment with small size and high efficiency. It has wide application prospects in industry. However, due to the highly compact structure, it is difficult to measure the wall temperature of heat transfer surface by traditional test methods. For measuring the thermal performance of compact heat transfer surfaces more accurately, a single-blow transient test technique using pulse change inlet condition with optimized pulse width and matching time is developed. By turning on and off the electric air heater, the pulse change in the inlet temperature can be realized and is fitted as the superposition of a positive and a negative exponential function with a time shift. In order to reduce the effect of the uncertainty of temperature measurement, the optimum pulse width and optimum matching time is obtained by numerical calculations. By means of the newly extended test method, the heat transfer performance of a parallel-plate test core is measured and compared with the results from the literature. The analysis shows that the present pulse change technique considering the optimal pulse width and matching time have to be considered for the heat transfer surfaces with NTU > 4.5 to reduce the uncertainty in temperature measurement. The experimental results are in good agreement with those given in the literature.

Nomenclature

\( \overline{a} \)

Dimensionless pulse width

A

Total heat transfer surface area of test core, m2

B

Ratio of heat capacity of fluid in test core to that of solid wall

cp,f

Specific heat capacity of fluid at constant pressure, J/kgK

cw

Specific heat of solid material, J/kgK

E

Error amplification factor

j

Colburn j factor

L

Total length of test core, m

\( {\dot{m}}_{\mathrm{f}} \)

Mass flow rate of fluid, kg/s

Mf

Mass of the fluid in the test core, kg

Mw

Mass of the solid matrix of the test core, kg

NTU

Number of heat transfer units, dimensionless

Re

Reynolds number, the ratio of inertial forces to viscous forces, dimensionless

Tf

Fluid temperature, K

Tf,max

Maximum fluid temperature, K

T0

Initial fluid and solid material temperature, K

Tw

Solid material temperature, K

vfr

Frontal free flow velocity of the air heater, m/s

x

Length coordinate, m

\( \overline{x} \)

Dimensionless length variable, dimensionless

Greek symbols

α

Mean heat transfer coefficient, W/m2K

τ*

Time constant of exponential inlet temperature change, s

\( \overline{\tau} \)

Dimensionless time

\( {\overline{\tau}}^{\ast } \)

Dimensionless time constant of exponential inlet temperature change

θf

Dimensionless fluid temperature

θw

Dimensionless solid wall temperature

Subscript

f

Fluid

in

Inlet

op

Optimal

w

Solid wall

Superscript

E

exponential change in inlet

U

Step change in inlet

Notes

Acknowledgements

The authors are grateful for the financial support from the Higher Education Discipline Innovation Project (111 Project) under the funding code B13020.

References

  1. 1.
    Pucci PF, Howard CP (1967) The single blow transient testing technique for compact heat exchanger surfaces. Journal of Engineering for Power 89(1):29–38CrossRefGoogle Scholar
  2. 2.
    Hausen H (1929) Über die Theorie des Wärmeaustausches in Regeneratoren. Z Angew Math Mech 9(3):173–200CrossRefGoogle Scholar
  3. 3.
    Schumann TEW (1929) Heat transfer: a liquid flowing through a porous prism. J Frankl Inst 8(3):405–416CrossRefGoogle Scholar
  4. 4.
    Furnas CC (1930) Heat transfer from a gas stream to a bed of broken solids. Ind Eng Chem 22(1):26–31CrossRefGoogle Scholar
  5. 5.
    Furnas CC (1930) Heat transfer from a gas stream to a bed of broken solids. Ind Eng Chem 22(7):721–731CrossRefGoogle Scholar
  6. 6.
    Locke GL (1950) Heat transfer and flow friction characteristics of porous solids. Technical Report 10, Stanford University, Department of Mechanical EngineeringGoogle Scholar
  7. 7.
    Mondt JR, Siegla DC (1974) Performance of perforated heat exchanger surfaces. Journal of Engineering for Power 96(2):81–86CrossRefGoogle Scholar
  8. 8.
    Howard CP (1964) The single-blow problem including the effect of longitudinal conduction. ASME Paper 1964, No. 64-GTP-11Google Scholar
  9. 9.
    Kohlmayr GF (1966) Exact maximum slopes for transient matrix heat-transfer testing. Int J Heat Mass Transf 9(7):671–680CrossRefGoogle Scholar
  10. 10.
    Kohlmayr GF (1967) Extension of the maximum slope method to arbitrary upstream fluid temperature changes. J Heat Transf 90(1):130–134CrossRefGoogle Scholar
  11. 11.
    Kohlmayr GF (1968) An indirect curve matching method for transient matrix heat-transfer testing in the low NTU-range. Int J Heat Mass Transf 11(3):567–581CrossRefGoogle Scholar
  12. 12.
    Liang CY, Yang WJ (1975) Modified single-blow technique for performance evaluation on heat transfer surfaces. J Heat Transf 97(1):16–21CrossRefGoogle Scholar
  13. 13.
    Cai ZH, Li ML, Wu YW (1984) A modified selected point matching technique for testing compact heat exchanger surfaces. Int J Heat Mass Transf 27(7):971–978CrossRefGoogle Scholar
  14. 14.
    Mullisen RS, Loehrke RI (1986) A transient heat exchanger evaluation test for arbitrary fluid inlet temperature variation and longitudinal core conduction. J Heat Transf 108(2):370–376CrossRefGoogle Scholar
  15. 15.
    Loehrke RI (1990) Evaluating the results of the single-blow transient heat exchanger test. Exp Thermal Fluid Sci 3(6):574–580CrossRefGoogle Scholar
  16. 16.
    Zhou C, Cai Z, Li M (1991) A perturbation solution of transient technique for testing compact heat exchanger surfaces, in: Numerical Methods in Thermal Problem, Lewis RW, Chin JH, Homsy GM (eds.), Pineridge, Swansea, 7(Part 2):1503–1513Google Scholar
  17. 17.
    Luo X, Roetzel W (2000) Theoretical study on the single-blow testing technique considering lateral heat resistance of fins in plate-fin heat exchangers. In: Wang B-X (ed) Heat Transfer Science and Technology, vol 2000. Higher Education Press, Beijing, pp 691–696Google Scholar
  18. 18.
    Luo X, Roetzel W (2001) The single-blow transient testing technique for plate-fin heat exchangers. Int J Heat Mass Transf 44(19):3745–3753CrossRefGoogle Scholar
  19. 19.
    Roetzel W, Luo X (1998) Extended temperature oscillation measurement technique for heat transfer and axial dispersion coefficients. Rev Gen Therm 37(4):277–283CrossRefGoogle Scholar
  20. 20.
    Zhou K, Luo X, Roetzel W (1998) Transient impulse test technique for heat transfer and axial dispersion coefficients. In: Proceedings of International Conference on Heat Exchangers for Sustainable Development, June 15–18, 1998, Lisbon, Portugal, Instituto Superrior Tecnico Lisboa, 645–652Google Scholar
  21. 21.
    Shi YH (2017) Test method for thermal performance of compact heat transfer structure based on pulse function transient method, M.Sc. theses, East China University of Science and Technology (in Chinese)Google Scholar
  22. 22.
    Stephan K (1959) Wärmeübertragung und Druckabfall bei nicht ausgebildeter Laminarströmung in Rohren und in ebenen Spalten. Chemie Ingenieur Technik 31(12):773–778CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghaiPeople’s Republic of China
  2. 2.Institute of ThermodynamicsGottfried Wilhelm Leibniz UniversityHannoverGermany

Personalised recommendations