Abstract
An experimental investigation has been conducted to clarify fouling effects of geothermal water scale deposited onto a surface upon its forced convection heat transfer characteristics. Examined is an elliptic cylinder of an axis ratio 1∶3, on which particles of silica scale are uniformly distributed. Local and mean heat transfer characteristics were measured for angles of attack 0° and 90°. Subsequently the fouling resistance is estimated from those results. Mean and turbulent fluctuating velocities were also measured in order to correlate the heat transfer features with the velocity field in the near wake of the elliptic cylinder.
Zusammenfassung
Um den Einfluß der Verschmutzung aus geothermischem Wasser an einer Oberfläche auf die Wärmeübertragung bei erzwungener Konvektion zu klären, wurde eine experimentelle Untersuchung durchgeführt. Dabei wird ein elliptischer Zylinder mit einem Achsenverhältnis von l ∶ 3 verwendet, über dem Kieselerdeteilchen gleichmäßig verteilt sind. Für Anströmwinkel von 0° und 90° wurde das örtliche und das mittlere Wärmeübergangsverhalten gemessen, daraus der Verschmutzungswiderstand bestimmt. Zudem wurden die mittleren und die turbulenten Schwankungsgeschwindigkeiten gemessen, um einen Zusammenhang zwischen dem Wärmeübertragungsverhalten und dem Geschwindigkeitsfeld im nahen Kielwasser des elliptischen Zylinders zu finden.
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- c :
-
length of major axis of clean elliptic cylinder
- E :
-
power spectrum
- f :
-
frequency of fluctuating velocity
- h :
-
local heat transfer coefficient=q(Tw−T∞)
- k :
-
size of scale particle
- M :
-
mesh number
- Nu :
-
local Nusselt number=hc/λ
- P :
-
probability density function
- q :
-
heat flux
- Re :
-
Reynolds number=U ∞ c/ν
- R f :
-
mean fouling resistance of scale
- s :
-
surface distance from leading edge of elliptic cylinder
- T w :
-
wall temperature
- T ∞ :
-
temperature of upstream uniform flow
- u :
-
streamwise component of turbulent fluctuating velocity
- U :
-
streamwise mean velocity
- U ∞ :
-
velocity of upstream uniform flow
- x :
-
distance from leading edge of elliptic cylinder in direction of upstream uniform flow
- y :
-
distance normal toxα angle of attack
- λ, ν:
-
thermal conductivity and kinematic viscosity of air at T∞
- c :
-
clean
- f :
-
fouled
- m :
-
mean
- min:
-
minimum
References
Wahl, E. F.: Geothermal Energy Utilization. New York' Wiley 1977
Mori, Y.; Suyama, J.: Reader of Geothermal Energy. Tokyo, Ohmsha 1980 (in Japanese)
Moresco, L. L.; Marshall, E.: Direct-contact heat transfer involving a scaling liquid. Letters in Heat Mass Transfer 8 (1981) 337–340
Bott, T. R.; Gudmundsson, J. S.: Rippled silica deposits in heat exchanger tubes. Heat Transfer-1978, 4 (1978) 373–378
Ota, T.; Aiba, S.; Taoka, Y; Kaido, Y; Koyama, S.: Forced convection heat transfer from an elliptic cylinder of axis ratio 1∶3. Preprint of JSME Meeting 811-1 (1981) 224–226
Ota, T.; Aiba, S.; Sugawara, S.: Forced convection heat transfer from an elliptic cylinder of axis ratio 1∶3. Preprint of 19th National Heat Transfer Symp. of Japan (1982) 85–87
Geothermal energy development center of Akita prefecture (1979)
Ota, T.; Aiba, S.; Tsuruta, T.; Kaga, M.: Forced convection heat transfer from an elliptic cylinder of axis ratio 1∶ 2. Bull. JSME 26 (1983) 262–267
Takeuchi, M.; Isshiki, N.; Ishibashi, Y.: Heat transfer on cylinders covered with close-fitting fabrics. Trans. JSME 48 (1982) 97–104
Achenbach, E.: Distribution of local pressure and skin friction around a circular cylinder in cross-flow up to Re=5×106. J. Fluid Mech. 34 (1968) 625–639
Aiba, S.; Ota, T.; Tsuchida, H.: Heat transfer and flow around a circular cylinder with tripping-wires. Wärme-Stoffübertrag. 12 (1979) 221–231
Knudsen, J. G.: Apparatus and techniques for measurement of fouling of heat transfer surfaces. In: Somerscales, E. F. C; Knudsen, J. G. (Eds.): Fouling of Heat Transfer Equipment (1981) 57–81
Patun, R. J.; Kreuger, R. H.; Starner, K. E.: Fouling studies and heat transfer test stand real time data acquisition system. In: Somerscales, E. F. C.; Knudsen, J. G. (Eds.): Fouling of Heat Transfer Equipment (1981)111–131
Watkinson, A. P.; Martinez, O.: Scaling of heat exchanger tubes by calcium carbonate. J. Heat Transfer 97 (1975) 504–508
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Ota, T., Nishiyama, H. Fouling effects of geothermal water scale upon heat transfer around an elliptic cylinder. Warme- und Stoffubertragung 19, 93–100 (1985). https://doi.org/10.1007/BF01682552
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DOI: https://doi.org/10.1007/BF01682552