Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-19T04:15:11.815Z Has data issue: false hasContentIssue false

The effect of the thermal prong—wire interaction on the response of a cold wire in gaseous flows (air, argon and helium)

Published online by Cambridge University Press:  20 April 2006

P. Paranthoen
Affiliation:
Laboratoire de Thermodynamique – L.A. C.N.R.S. N° 230. Faculté des Sciences et Techniques de Rouen, B.P. 67 76130 Mont-Saint-Aignan, France
C. Petit
Affiliation:
Laboratoire de Thermodynamique – L.A. C.N.R.S. N° 230. Faculté des Sciences et Techniques de Rouen, B.P. 67 76130 Mont-Saint-Aignan, France
J. C. Lecordier
Affiliation:
Laboratoire de Thermodynamique – L.A. C.N.R.S. N° 230. Faculté des Sciences et Techniques de Rouen, B.P. 67 76130 Mont-Saint-Aignan, France

Abstract

This paper deals with the study of the response of a cold wire used as a thermal sensor in a turbulent flow for different types of probes and for several gases (air, argon and helium). It is now well known that in the case of air flows the transfer function of the probe shows a typical step at low frequencies, as pointed out by Perry, Smits & Chong (1979).

In this plateau region the wire temperature may be influenced by the prong temperature through two different paths. The first is conduction between prong and wire, as already discussed by Maye (1970) using the ‘cold length’ lc, introduced by Betchov (1948). As suggested by Hojstrup, Rasmussen & Larsen (1975) the second is the result of the thermal boundary layer on the prong being very large at low velocities in gases of large thermal diffusivity; this region of influence (by the prong) extends over a length of the wire characterized by the thickness lb, of the thermal boundary layer on the prong.

In this paper a simple analysis of the behaviour of the transfer function of cold wires taking these two effects into account is presented by introducing the parameter η = lb/lc. An experimental investigation of these phenomena has been undertaken using a procedure which allows temperature fluctuations to be produced over a larger range of frequencies than has been usually made up to now.

Good agreement is obtained between experimental results and predictions using this analysis for several types of prong in different gaseous flows (air, argon and helium). An important step in the frequency response is found in the latter case because of the large thermal diffusivity of helium. Furthermore an example of the thermal prong–wire interaction is presented in the ease of intermittent temperature measurements.

Type
Research Article
Copyright
© 1982 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Antonia, R. A., Prabhu, A. & Stephenson, S. E. 1975 J. Fluid Mech. 72, 455.
Betchov, R. 1948 Proc. Ned. Akad. Wetenshappen 51, 721.
Collis, D. C. & Williams, M. J. 1959 J. Fluid Mech. 6, 351.
Comte-Bellot, G., Strohl, A. & Alcaraz, E. 1971 Trans. A.S.M.E. E: J. Appl. Mech. 38, 767.
Davies, A. E., Keffer, J. F. & Baines, W. D. 1975 Phys. Fluids 18, 770.
Fielder, H. 1978 In Proc. Dynamical Conf. Marseille—Baltimore—Skovlunde.
Freymuth, P. 1979 T.S.I. Q. 5, 18.
Fulachier, L. 1978 In Proc. Dynamical Conf. Marseille—Baltimore—Skovlunde.
Fulachier, L., Arzoumanian, E. & Dumas, R. 1978 In Proc. Symp. on Turbulence. Springer.
Hojstrup, J., Rasmussen, K. & Larsen, S. E. 1976 DISA Inf. no. 20.
Kramers, H. 1946 Physica 12, 61.
La Rue, J. C., Deaton, T. & Gibson, C. H. 1975 Rev. Sci. Instrum. 46, 757.
Lecordier, J. C., Petit, C. & Paranthoen, P. 1980 Lett. Heat Mass Transfer 7, 311.
Lecordier, J. C., Petit, C. & Paranthoen, P. 1981 Lett. Heat Mass Transfer 8, 103.
Maye, J. P. 1970 DISA Inf. no. 9.
Millon, F. 1977 Thèse de 3ème cycle, University of Rouen.
Paranthoen, P. & Petit, C. 1979 Lett. Heat Mass Transfer 6, 311.
Perry, A. E., Smits, A. J. & Chong, M. S. 1979 J. Fluid Mech. 90, 415.
Petit, C., Paranthoen, P. & Lecordier, J. C. 1981 Lett. Heat Mass Transfer 8, 281291.
Schacher, G. E. & Fairall, C. W. 1978 Rev. Sci. Instrum. 49, 1432.