Method to estimate water permeability functions of moderately wet soils with help of heat pipe technique

• Autorzy: Globus A.M. , Gee G.W. , Fayer M. , White M.

Warianty tytułu

PL

Metoda określania funkcji przepuszczalności umiarkowanie wilgotnych gleb przy pomocy techniki cieplnej rury

• Języki publikacji: EN

Abstrakty

EN

Water permeability of moderately wet soils, i.e., their unsaturated hydraulic conductivity and water diffusivity are seldom measured directly, yet are often needed by numerical models to simulate transport processes. These functions can be evaluated from steady state water content and temperature profiles in heat pipes - closed columns of uniformly moistened soil subjected to temperature gradient. For such systems Sw = DT/D(θ) = -dθ/dT where Sw is the thermogradient coefficient, DT is the thermal water diffusivity, D(θ) is isothermal water diffusivity and dθ/dT is the rate of change of water content with temperature deduced from steady state profiles of θ(x) and T(x), x - is the distance from one of column ends. DT varies in a relatively narrow range and can be assumed as a constant.Then D(θ) can be estimated as DTSw where Sw is measured in various locations along soil columns. Using water retention data, the steady water content profile can be procedure for estimating D(θ) can then be applied to estimate hydraulic conductivity, K(θ). Soil columns ranging in length from 5 to 10 cm, exposed to thermal gradients of l°C/cm for periods as short as 7 d, at initial suction values ranging from 1 to 1.5 MPa, can be used to estimate D and K with uncertainties of factor of five or less in the suction range from 0.03 to 3 Mpa.

PL

Zaproponowano metodę określania przepuszczalności hydraulicznej i dyfuzyjności wodnej gleby na podstawie profili ustalonej zawartości wody i temperatury w cieplnych rurach - zamkniętych kolumnach z równomiernie zwilżoną glebą poddaną gradientowi temperatury.

Słowa kluczowe

EN

soil; hydraulic conductivity; water diffusivity coefficient; heat pipe technique; water permeability

• Wydawca: -
• Czasopismo: Zeszyty Problemowe Postępów Nauk Rolniczych
• Rocznik: 1996
• Tom: 436
• Opis fizyczny: p.49-55,fig.,ref.

Twórcy

autor

Globus A.M.

• Agrophysical Research Institute, Russian Academy of Agricultural Sciences, Grazhdansky 14, St.Petersburg, 195220, Russia

autor

Gee G.W.

• Pacific Northwest Laboratory, Richland, WA, 99352, USA

autor

Fayer M.

• Pacific Northwest Laboratory, Richland, WA, 99352, USA

autor

White M.

• Pacific Northwest Laboratory, Richland, WA, 99352, USA

Bibliografia

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