Heat transfer in porous media considering phase change and capillarity—the heat pipe effect

Udell, Kent S.

doi:10.1016/0017-9310(85)90082-1

Cited by 409 publications

(177 citation statements)

References 15 publications

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“…The thermodynamic equilibrium of these interfaces are given by a combination of Clausius-Clapeyron and Kelvin's equations. These two criteria can be combined to obtain a relationship between the local thermodynall!-ic conditions which must be satisfied for an interface to exist in steady-state· (Udell, 1985). But, when one of the fluid phases is submicroscopically thin, which is invariably the case when an interface comes near the contact zone on a solid wall, the effect of long-range dispersion interactions between the film phase and .the solid wall come into effect.…”

Section: Superheat For Surface Nucleationmentioning

confidence: 99%

“…These channels could be formed either along the contact surfaces be.tween the glass beads and the confining tube and/or within the porous medium itself (Udell, 1985).…”

Section: Effect Of Channelingmentioning

confidence: 99%

“…This condition combined with the Young-Laplace equation was used by Udell (1985) to show that the only stable configurations are those in which the liquid phase resides on the convex side of the menisci and it is at a lower pressure than the vapor phase, which is superheated. He also developed an expression for the local temperature in terms of local thermodynamic properties and capillary pressure for pure liquid-vapor systems.…”

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confidence: 99%

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Effects of phase transformation of steam-water relative permeabilities

Verma¹

1986

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Section: Superheat For Surface Nucleationmentioning

confidence: 99%

“…These channels could be formed either along the contact surfaces be.tween the glass beads and the confining tube and/or within the porous medium itself (Udell, 1985).…”

Section: Effect Of Channelingmentioning

confidence: 99%

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confidence: 99%

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Effects of phase transformation of steam-water relative permeabilities

Verma¹

1986

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“…Such conditions often result in strong counterflow of liquid and gas phases and significant convective transfer of heat, commonly known as geologic "heat pipes" (e.g., Udell, 1985;Pruess, 1990, 1992). Originally, the term "heat pipe" described engineered devices-typically hollow cylinders filled with a vaporizable liquid-that are used in many industrial applications to increase the efficiency of heat transport.…”

Section: Introductionmentioning

confidence: 99%

“…A thorough understanding of geologic heat pipes and their effect on flow and transport processes is essential, for example, in vapor-dominated geothermal systems such as the Geysers in California (e.g., Pruess, 1985), in thermally enhanced oil recovery, and in subsurface systems affected from buried pipelines and electrical cables (Udell, 1985).…”

Section: Introductionmentioning

confidence: 99%

A Temperature-Profile Method for Estimating Flow Processes in Geologic Heat Pipes

Birkhölzer¹

2005

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Above-boiling temperature conditions, as encountered, for example, in geothermal reservoirs and in geologic repositories for the storage of heat-producing nuclear wastes, may give rise to strongly altered liquid and gas flow processes in porous subsurface environments. The magnitude of such flow perturbation is extremely hard to measure in the field. We therefore propose a simple temperature-profile method that uses high-resolution temperature data for deriving such information. The energy that is transmitted with the vapor and water flow creates a nearly isothermal zone maintained at about the boiling temperature, referred to as a heat pipe. Characteristic features of measured temperature profiles, such as the differences in the gradients inside and outside of the heat pipe regions, are used to derive the approximate magnitude of the liquid and gas fluxes in the subsurface, for both steady-state and transient conditions.-1 -1.

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Porous Nickel Coatings on Steel Tubes Formed by Aqueous Colloidal Processing

Ferrari¹,

Sánchez-Herencia

Moreno³

2002

Adv. Eng. Mater.

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ExperimentalInorganic fullerene-like WS 2 nanoparticles were synthesized using WO 3 powders as a precursor materials by a solid-gas reaction according to a procedure described elsewhere. [21] WS 2 particles (platelets of the 2H polytype) with average size of between 600±1700 nm were purchased from Aldrich. Electroless Ni-based composite coatings were deposited on the surface of the test ring and block fabricated from a mild carbon steel by electroless co-deposition. The bath compositions and conditions for the electroless coatings are: nickel sulfate 20±25 g/L, sodium hypophosphite 20±25g/L, sodium acetate 10±15 g/L, acetic acid 5±10 mL/L, surface agent 200±400 mg/L, IF-WS 2 , 2H-WS 2 , graphite or 6H-SiC 6.0 g/L, pH = 4.5±5.1, temperature at 80±85 C. Ni-P coating was firstly deposited for 0.5 h and then Ni-P-(IF-WS 2 ) was deposited for 2.5 h. For comparison, the Ni-P, Ni-P-SiC, Ni-P-(2H-WS 2 ) and Ni-P-graphite coatings were deposited on the test ring and block according to a similar procedure. The crystal structures of the as-prepared electroless composite coatings were analyzed by XRD (Philips X Pert MPD, Cu K a1 ). In this work, the electroless Ni-P-based composite coatings were treated at 673 K for 2 h in vacuum.The wear and friction parameters of the electroless composite coatings were measured using a MHK 500 ring-on-block friction testing machine, whose friction pairs consist of rotation ring (diameter in 49.24 mm, thickness in 13.00 mm) and static block (12.35 mm 12.35 mm 19.00 mm). The main axis rotation speed is 800 r/min, and 46# lubricant oil was used as lubricant. After running in at a load of 200 N for 20 min, the mass loss and friction coefficient were measured at a fixed load of 700 N, testing time last for 6 h. The wear resistance was evaluated according to the mass loss of the block specimen after wear testing. The worn surfaces of the electroless composite coatings on the blocks were observed by SEM (JEOL JSM-5600LV).

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Heat transfer in porous media considering phase change and capillarity—the heat pipe effect

Cited by 409 publications

References 15 publications

Effects of phase transformation of steam-water relative permeabilities

Effects of phase transformation of steam-water relative permeabilities

A Temperature-Profile Method for Estimating Flow Processes in Geologic Heat Pipes

Porous Nickel Coatings on Steel Tubes Formed by Aqueous Colloidal Processing

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