Effective Thermal Conductivity of Saturated Sintered Nickel Loop Heat Pipe Wicks

Bonnefoy, M.; Ochterbeck, J. M.; Drolen, Bruce L.; Nikitkin, Michael; Aerospace, Swales

doi:10.2514/6.2004-2571

Cited by 4 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Porosity, effective pore radius, and liquid permeability were determined using imbibition, capillary flow porometry, and pressure-flow rate data, respectively. The authors determined that many of the correlations in the literature for pore size and permeability are too general in nature, echoing the conclusions of Bonnefoy and Ochterbeck [12] in regard to effective thermal conductivity.…”

Section: Loop Heat Pipementioning

confidence: 88%

Porous Structures in Heat Pipes

Němec¹

2018

Porosity - Process, Technologies and Applications

View full text Add to dashboard Cite

This work deals with heat pipes with porous wick structures and experiments depending on the wick structure porosity, because the porosity is one of the wick structure properties which has effect on the heat transport ability of the heat pipe. The work describes manufacturing porous wick structures for wick heat pipe by sintering of copper metal powders with various powder grain size; manufacturing porous wick structures for loop heat pipe by sintering of copper and nickel metal powders with various powder grain size; influence of manufacturing technology on the wick structure porosity by microscopic analysis of the porous structure; design and construction of wick heat pipe and loop heat pipes; experimental determination influence of the wick structure porosity on the heat transport ability of loop heat pipes at various conditions; and experimental and mathematical determination influence of the wick structure porosity on the heat transport ability of wick heat pipes at various conditions.

show abstract

Section: Loop Heat Pipementioning

confidence: 88%

Porous Structures in Heat Pipes

Němec¹

2018

Porosity - Process, Technologies and Applications

View full text Add to dashboard Cite

show abstract

“…There are several models for evaluation of thermal conductivity of wicks saturated with liquid [21]. Here, effective thermal conductivity of the wick is calculated using k we k l 1 k w .…”

Section: Heat Transfer and Pressure Drop In The Evaporator Wickmentioning

confidence: 99%

“…(19)] and energy balance in the core [Eq. (21)] are solved simultaneously for T 5 and 5 . For an LHP, by virtue of assumption 10, T r T 5 .…”

Section: Evaluation Of Thermodynamic State Of the Core In An Lhpmentioning

confidence: 99%

“…In an LHP Eqs. (19) and (21) are solved to determine the state of the core and CC. MWF in the evaporator is then calculated using Eq.…”

Section: Algorithm A2mentioning

confidence: 99%

“…The energy equation in the core [Eq. (21)] is solved to evaluate T 1 using Newton-Raphson method. The term F LHP , used in A1-LHP for the T 1 update equation is…”

Section: Algorithm A1-lhpmentioning

confidence: 99%

See 2 more Smart Citations

Thermohydraulic Modeling of Capillary Pumped Loop and Loop Heat Pipe

Adoni¹,

Ambirajan²,

Jasvanth³

et al. 2007

Journal of Thermophysics and Heat Transfer

View full text Add to dashboard Cite

Capillary pumped loop (CPL) and loop heat pipe (LHP) are passive heat transport devices that are gaining importance as a part of the thermal control system of modern high power spacecraft. A mathematical model to simulate the thermohydraulic performance of CPLs and LHPs is required for the design of such a thermal control system. In this study a unified mathematical model to estimate thermal and hydraulic performance of a CPL and an LHP with a two-phase or a hard-filled reservoir is presented. The steady-state model is based on conservation of energy and mass in the system. Heat exchange between the loop and the surroundings and pressure drops in the loop are calculated. This study presents the results of numerical studies on a CPL and an LHP. The constant conductance regime in a CPL or an LHP occurs when the reservoir is hard-filled. It also occurs in an LHP if the condenser is fully used. The heat leak across the wick becomes significant in a hard-filled LHP because the core is no longer saturated and hence the mass flow rate must be calculated using an energy balance on the outer surface of the wick. Nomenclatureenergy imbalance in the evaporator core and CC, W f = Darcy friction factor G = mass velocity, kg m 2 s 1 H = heat transfer coefficient, W m 2 K 1 h = enthalpy, J kg 1 K = wick permeability, m 2 k = thermal conductivity, W m 1 K 1 L = length, m L cond = length of condenser, m L condensation = length of condensation, m L evap-rt = distance between points 7 and 4, m L rt-hydr = vertical distance between loop and the reservoir, m L step = refers to step size in RKM, m M = mass of working fluid, kg _ m = mass flow rate, kg s 1 P = pressure, Pa Q = heat, W Q deprime = heat load at which CPL deprimes for limited condenser length, W Q hf = heat load at which reservoir is hard-filled, W Q open = heat load at which condenser fully opens, W r = radius, m T = temperature, K t = thickness, m U = overall heat transfer coefficient, W m 2 K 1 u = velocity, m s 1 V = volume, m 3 x = dryness fraction of vapor z = length, m v = void fraction, A v =A = volume fraction of liquid in the reservoir = perimeter, m = porosity " = numerical error (convergence criterion) # = normalized energy imbalance = conductance, W K 1 = density, kg m 3 = surface tension, N m 1 = two-phase friction multiplier Subscripts acc = acceleration c = core cond = condenser cond 0 = refers to region where condensation is occurring e = effective evap = evaporator ex = exchange f = friction fg = difference in thermodynamic property in liquid and vapor phase g = groove i = inner part of tube ins = insulation L = leak l = liquid ll = liquid line lo = liquid only load = refers to heat load applied externally loop = part of the system excluding the reservoir o = outer part of tube P = pressure r = reservoir/radial res = reservoir sc = subcooler sink = sink of condenser t = tube/evaporator teeth tp = two-phase v = vapor/(volume in case of specific heat) vl = vapor line vo = vapor only w = wick wp = wick pore ws = particle diameter in sintering z = length dir...

show abstract