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Effect of Probe Deflection on Dual‐Probe Heat‐Pulse Thermal Conductivity Measurements
Author(s) -
Kluitenberg Gerard J.,
Kamai Tamir,
Vrugt Jasper A.,
Hopmans Jan W.
Publication year - 2010
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2010.0016n
Subject(s) - deflection (physics) , thermal conductivity , materials science , conductivity , thermal , optics , analytical chemistry (journal) , composite material , chemistry , thermodynamics , physics , environmental chemistry
The dual‐probe heat‐pulse (DPHP) method is useful for measuring soil thermal properties; however, the probes of a DPHP sensor can deflect when inserted into the soil. Theoretical analysis has shown that measurements of thermal conductivity (λ) should be unaffected by deflection‐induced changes in probe spacing. To verify this result, the conductivities of water, dry sand, and saturated sand were measured using DPHP sensors with probes subject to inward deflection, no deflection, and outward deflection. No error in λ was detected when probes were deflected inward by an amount that caused a 14% reduction in probe spacing. Outward deflection (15% increase in spacing) caused error in λ estimates, but the errors were small (≤0.04 W m −1 K −1 ) and likely to be of little consequence in most applications. We conclude that estimates of λ obtained with the DPHP method are largely unaffected by changes in probe spacing caused by deflection.