GRAPHENE

radiation heat fluxes: Topics by Science

  • Mixing charges and vertical warmth fluxes north of Svalbard from Arctic winter to spring

    NASA Astrophysics Information System (ADS)

    Meyer, Amelie; Fer, Ilker; Sundfjord, Arild; Peterson, Algot Ok.

    2017-06-01

    Mixing and warmth flux charges collected within the Eurasian Basin north of Svalbard through the N-ICE2015 drift expedition are offered. The observations cowl the deep Nansen Basin, the Svalbard continental slope, and the shallow Yermak Plateau from winter to summer time. Imply quiescent winter warmth flux values within the Nansen Basin are 2 W m-2 on the ice-ocean interface, 3 W m-2 within the pycnocline, and 1 W m-2 under the pycnocline. Giant warmth fluxes exceeding 300 W m-2 are noticed within the late spring near the floor over the Yermak Plateau. The info consisting of 588 microstructure profiles and 50 days of high-resolution under-ice turbulence measurements are used to quantify the impression of a number of forcing elements on turbulent dissipation and warmth flux charges. Wind forcing will increase turbulent dissipation seven occasions within the higher 50 m, and doubles warmth fluxes on the ice-ocean interface. The presence of heat Atlantic Water near the floor will increase the temperature gradient within the water column, resulting in enhanced warmth flux charges inside the pycnocline. Steep topography persistently enhances dissipation charges by an element of 4 and episodically will increase warmth flux at depth. It’s, nonetheless, the mixture of storms and shallow Atlantic Water that results in the best warmth flux charges noticed: ice-ocean interface warmth fluxes common 100 W m-2 throughout peak occasions and are related to speedy basal sea ice soften, reaching 25 cm/d.

  • A mannequin of warmth move within the sheep uncovered to excessive ranges of photo voltaic radiation.

    PubMed

    Vera, R R; Koong, L J; Morris, J G

    1975-08-01

    The fleece is a crucial part in thermoregulation of sheep uncovered to excessive ranges of photo voltaic radiation. A mannequin written in CSMP has been developed which represents the move of vitality between the sheep and its surroundings. This mannequin relies on a set of differential equations which describe the flux of warmth between the elements of the system–fleece, tip, pores and skin, physique and surroundings. It requires as enter parameters location, date, time of day, temperature, relative humidity, cloud cowl, wind motion, animal weight and linear measurements and fleece size. At every integration interval incoming photo voltaic radiation and its elements, the warmth arising from the animal’s metabolism and the warmth trade by long-wave radiation, convection, conduction and evaporative cooling are computed. Temperatures on the fleece tip, pores and skin and physique core are monitored.

  • Mesoscale eddies management meridional warmth flux variability within the subpolar North Atlantic

    NASA Astrophysics Information System (ADS)

    Zhao, Jian; Bower, Amy; Yang, Jiayan; Lin, Xiaopei; Zhou, Chun

    2017-04-01

    The meridional warmth flux within the subpolar North Atlantic is significant to the local weather of the high-latitude North Atlantic. For the basinwide warmth flux throughout a bit between Greenland and Scotland, a lot of the variability happens within the Iceland basin, the place the North Atlantic Present (NAC) carries comparatively heat and salty water northward. As a part of the Overturning within the Subpolar North Atlantic Program (OSNAP), WHOI and OUC are collectively working gliders within the Iceland Basin to repeatedly monitor the circulation and corresponding warmth flux on this eddy-rich area. Primarily based on one 12 months of observations, two circulation regimes within the Iceland basin have been recognized: a mesoscale eddy like circulation sample and northward NAC circulation sample. When a mesoscale eddy is generated, the rotational currents related to the eddy result in each northward and southward move within the Iceland basin. That is fairly completely different from the broad northward move related to the NAC when there isn’t any eddy. The transition between the 2 regimes coupled with the sturdy temperature entrance within the Iceland basin can modify the meridional warmth flux on the order of 0.3PW, which is the dominant supply for the warmth flux change the Iceland Basin. In line with high-resolution numerical mannequin outcomes, the Iceland Basin has the biggest contribution to the meridional warmth flux variability alongside the part between Greenland and Scotland. Subsequently, mesoscale eddies within the Iceland Basin present essential dynamics to regulate the meridional warmth flux variability within the subpolar North Atlantic.

  • Institute for Excessive Warmth Flux Removing (IHHFR). Phases I, II, and III

    SciTech Join

    Boyd, Ronald D.

    2014-08-31

    The IHHFR centered on interdisciplinary purposes because it pertains to excessive warmth flux engineering points and issues which come up as a result of engineering methods being miniaturized, optimized, or requiring elevated excessive warmth flux efficiency. The work within the IHHFR centered on water as a coolant and contains: (1) the event, design, and development of the excessive warmth flux move loop and facility; (2) check part growth, design, and fabrication; and, (3) single-side warmth flux experiments to provide 2-D boiling curves and 3-D conjugate warmth switch measurements for single-side heated check sections. This work offers information for comparisons with beforehand developed andmore » new single-side heated correlations and approaches that handle the single-side heated impact on warmth switch. As well as, this work contains the addition of single-side heated round TS and a monoblock check part with a helical wire insert. Lastly, the current work contains: (1) information base enlargement for the monoblock with a helical wire insert (just for the latter geometry), (2) prediction and verification utilizing finite ingredient, (3) monoblock mannequin and methodology growth analyses, and (4) an alternate mannequin growth for a hypervapotron and associated conjugate warmth switch controlling parameters.« much less

  • Warmth flux variations over sea-ice noticed on the coastal space of the Sejong Station, Antarctica

    NASA Astrophysics Information System (ADS)

    Park, S.; Choi, T.; Kim, S.

    2012-12-01

    This examine presents variations of wise warmth flux and latent warmth flux over sea-ice noticed in 2011 from the 10-m flux tower positioned on the coast of the Sejong Station on King George Island, Antarctica. A interval from June to November was divided into three elements: “Freezing”, “Frozen”, and “Melting” intervals primarily based on day by day monitoring of sea state and hourly images wanting on the Marian Cove in entrance of the Sejong Station. The division of intervals enabled us to look into the warmth flux variations relying on the sea-ice situations. Over freezing sea floor through the freezing interval of late June, day by day imply wise warmth flux was -11.9 Wm-2 and day by day imply latent warmth flux was +16.3 Wm-2. Over the frozen sea-ice, day by day imply wise warmth flux was -10.4 Wm-2 whereas day by day imply latent warmth flux was +2.4 Wm-2. In the course of the melting interval of mid-October to early November, magnitudes of wise warmth flux elevated to -14.2 Wm-2 and latent warmth flux additionally elevated to +13.5 Wm-2. Briefly, latent warmth flux was normally upward over sea-ice more often than not whereas wise warmth flux was downward from ambiance to sea-ice. Magnitudes of the fluxes had been small however elevated when freezing or melting of sea-ice was occurring. Particularly, latent warmth flux elevated 5 to 6 occasions in comparison with that of “frozen” interval implying that early melting of sea-ice could trigger 5 to 6 occasions bigger provide of moisture to the ambiance.

  • Unsteady Warmth-Flux Measurements of Second-Mode Instability Waves in a Hypersonic Boundary Layer

    NASA Technical Reviews Server (NTRS)

    Kergerise, Michael A.; Rufer, Shann J.

    2016-01-01

    On this paper we report on the applying of the atomic layer thermopile (ALTP) heat- flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat plate boundary layer. The centerline of the flat-plate mannequin was instrumented with a streamwise array of ALTP sensors and the flat-plate mannequin was uncovered to a Mach 6 freestream over a variety of unit Reynolds numbers. Right here, we noticed an unstable band of frequencies which are related to second-mode instability waves within the laminar boundary layer that types on the flat-plate floor. The measured frequencies, group velocities, part speeds, and wavelengths of those instability waves are in settlement with information beforehand reported within the literature. Warmth flux time sequence, and the Morlet-wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. As well as, a laser-based radiative heating system was developed to measure the frequency response features (FRF) of the ALTP sensors used within the wind tunnel check. These measurements had been used to evaluate the steadiness of the sensor FRFs over time and to right spectral estimates for any attenuation brought on by the finite sensor bandwidth.

  • On the Interplay between Marine Boundary Layer Mobile Cloudiness and Floor Warmth Fluxes

    SciTech Join

    Kazil, J.; Feingold, G.; Wang, Hailong

    2014-01-02

    The interplay between marine boundary layer mobile cloudiness and floor uxes of wise and latent warmth is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind velocity. The Superior Analysis WRF mannequin is used to conduct cloud-system-resolving simulations with interactive floor fluxes of wise warmth, latent warmth, and of sea salt aerosol, and with an in depth illustration of the interplay between aerosol particles and clouds. The mechanisms answerable for the temporal evolution and spatial distribution of the floor warmth fluxes within the closed- and open-cell state are investigated and defined. Itmore » is discovered that the horizontal spatial construction of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of floor air temperature and water vapor, and, to a lesser diploma, of the floor wise and latent warmth flux. The synchronized dynamics of the the open-cell state drives oscillations in floor air temperature, water vapor, and within the floor fluxes of wise and latent warmth, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are recognized nearly as good predictors of the spatial distribution of floor air temperature and wise warmth flux, however not of floor water vapor and latent warmth flux. It’s proven that by enhancing the floor wise warmth flux, the open-cell state creates situations by which it’s maintained. Whereas the open-cell state into account is just not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it additionally enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted situations, this enhancement could replenish the aerosol wanted for cloud formation, and therefore contribute to the perpetuation of the open-cell state as nicely. Spatial homogenization of the floor fluxes is discovered

  • Nanoporous membrane system for extremely excessive warmth flux thermal administration

    NASA Astrophysics Information System (ADS)

    Hanks, Daniel F.; Lu, Zhengmao; Sircar, Jay; Salamon, Todd R.; Antao, Dion S.; Bagnall, Kevin R.; Barabadi, Banafsheh; Wang, Evelyn N.

    2018-02-01

    Excessive energy density electronics are severely restricted by present thermal administration options that are unable to dissipate the required warmth flux whereas sustaining protected junction temperatures for dependable operation. We designed, fabricated, and experimentally characterised a microfluidic system for ultra-high warmth flux dissipation utilizing evaporation from a nanoporous silicon membrane. With 100 nm diameter pores, the membrane can generate excessive capillary stress even with low floor pressure fluids akin to pentane and R245fa. The suspended ultra-thin membrane construction facilitates environment friendly liquid transport with minimal viscous stress losses. We fabricated the membrane in silicon utilizing interference lithography and reactive ion etching after which bonded it to a excessive permeability silicon microchannel array to create a biporous wick which achieves excessive capillary stress with enhanced permeability. The again aspect consisted of a skinny movie platinum heater and resistive temperature sensors to emulate the warmth dissipation in transistors and measure the temperature, respectively. We experimentally characterised the gadgets in pure vapor-ambient situations in an environmental chamber. Accordingly, we demonstrated warmth fluxes of 665 ± 74 W/cm2 utilizing pentane over an space of 0.172 mm × 10 mm with a temperature rise of 28.5 ± 1.8 Ok from the heated substrate to ambient vapor. This warmth flux, which is normalized by the evaporation space, is the best reported thus far within the pure evaporation regime, that’s, with out nucleate boiling. The experimental outcomes are in good settlement with a excessive constancy mannequin which captures warmth conduction within the suspended membrane construction in addition to non-equilibrium and sub-continuum results on the liquid-vapor interface. This work means that evaporative membrane-based approaches may be promising in the direction of realizing an environment friendly, excessive flux thermal administration technique over massive areas for high-performance electronics.

  • Evaporation on/in Capillary Constructions of Excessive Warmth Flux Two-Section Units

    NASA Technical Reviews Server (NTRS)

    Faghri, Amir; Khrustalev, Dmitry

    1996-01-01

    Two-phase gadgets (warmth pipes, capillary pumped loops, loop warmth pipes, and evaporators) have turn out to be acknowledged as key parts in thermal management methods of area platforms. Capillary and porous buildings are mandatory and broadly utilized in these gadgets, particularly in excessive warmth flux and zero-g purposes, to supply fluid transport and enhanced warmth switch throughout vaporization and condensation. Nonetheless, some surprising important phenomena, akin to dryout in lengthy warmth pipe evaporators and excessive thermal resistance of loop warmth pipe evaporators with excessive warmth fluxes, are attainable and have been encountered in the usage of two-phase gadgets within the low gravity surroundings. Subsequently, an in depth basic investigation is proposed to raised perceive the fluid habits in capillary-porous buildings throughout vaporization at excessive warmth fluxes. The current paper addresses some theoretical elements of this investigation.

  • Warmth flux trade estimation by utilizing ATSR SST information in TOGA space

    NASA Astrophysics Information System (ADS)

    Xue, Yong; Lawrence, Sean P.; Llewellyn-Jones, David T.

    1995-12-01

    The examine of phenomena akin to ENSO requires consideration of the dynamics and thermodynamics of the coupled ocean-atmosphere system. The dynamic and thermal properties of the ambiance and ocean are straight affected by air-sea transfers of fluxes of momentum, warmth and moisture. On this paper, we current outcomes of turbulent warmth fluxes calculated by utilizing two years (1992 and 1993) month-to-month common TOGA information and ATSR SST information in TOGA space. A comparability with revealed outcomes signifies good qualitative settlement. Additionally, we in contrast the outcomes of warmth flux trade by utilizing ATSR SST information and by utilizing the TOGA bucket SST information. The ATSR SST information set has been proven to be helpful in serving to to estimate the big area scale warmth flux trade.

  • Viscous rest of Ganymede’s impression craters: Constraints on warmth flux

    USGS Publications Warehouse

    Bland, Michael T.; Singer, Kelsi N.; McKinnon, William B.; Schenk, Paul M.

    2017-01-01

    Measurement of crater depths in Ganymede’s darkish terrain have revealed substantial numbers of unusually shallow craters indicative of viscous rest [see companion paper: Singer, K.N., Schenk, P. M., Bland, M.T., McKinnon, W.B., (2017). Relaxed impact craters on Ganymede: Regional variations and high heat flow. Icarus, submitted]. These viscously relaxed craters present perception into the thermal historical past of the darkish terrain: the speed of rest is dependent upon the dimensions of the crater and the thermal construction of the lithosphere. Right here we use finite ingredient simulations of crater rest to constrain the warmth flux inside the darkish terrain when rest occurred. We present that the diploma of viscous rest noticed can’t be achieved via radiogenic heating alone, even when all the relaxed craters are historic and skilled the excessive radiogenic fluxes current early within the satellite tv for pc’s historical past. For craters with diameter ≥ 10 km, warmth fluxes of 40–50 mW m-2−2″> can reproduce the noticed crater depths, however provided that the fluxes are sustained for ∼1 Gyr. These craters will also be defined by shorter-lived “warmth pulses” with magnitudes of ∼100 mW m-2−2″> and timescales of 10–100 Myr. At small crater diameters (4 km) the noticed shallow depths are tough to attain even when warmth fluxes as excessive as 150 mW m-2−2″> are sustained for 1 Gyr. The intense thermal situations required to viscously loosen up small craters could point out that mechanisms aside from viscous rest, akin to topographic degradation, are additionally in play at small crater diameters. The timing of the relief occasion(s) is poorly constrained as a result of sparsity of ample topographic data, although it probably occurred in Ganymede’s center historical past (neither not too long ago, nor shortly after satellite tv for pc formation). The consistency between the timing and magnitude of the warmth fluxes derived right here and people inferred from different tectonic options suggests {that a} single occasion

  • Viscous rest of Ganymede’s impression craters: Constraints on warmth flux

    NASA Astrophysics Information System (ADS)

    Bland, Michael T.; Singer, Kelsi N.; McKinnon, William B.; Schenk, Paul M.

    2017-11-01

    Measurement of crater depths in Ganymede’s darkish terrain have revealed substantial numbers of unusually shallow craters indicative of viscous rest [see companion paper: Singer, K.N., Schenk, P. M., Bland, M.T., McKinnon, W.B., (2017). Relaxed impact craters on Ganymede: Regional variations and high heat flow. Icarus, submitted]. These viscously relaxed craters present perception into the thermal historical past of the darkish terrain: the speed of rest is dependent upon the dimensions of the crater and the thermal construction of the lithosphere. Right here we use finite ingredient simulations of crater rest to constrain the warmth flux inside the darkish terrain when rest occurred. We present that the diploma of viscous rest noticed can’t be achieved via radiogenic heating alone, even when all the relaxed craters are historic and skilled the excessive radiogenic fluxes current early within the satellite tv for pc’s historical past. For craters with diameter ≥ 10 km, warmth fluxes of 40-50 mW m-2 can reproduce the noticed crater depths, however provided that the fluxes are sustained for ∼1 Gyr. These craters will also be defined by shorter-lived “warmth pulses” with magnitudes of ∼100 mW m-2 and timescales of 10-100 Myr. At small crater diameters (4 km) the noticed shallow depths are tough to attain even when warmth fluxes as excessive as 150 mW m-2 are sustained for 1 Gyr. The intense thermal situations required to viscously loosen up small craters could point out that mechanisms aside from viscous rest, akin to topographic degradation, are additionally in play at small crater diameters. The timing of the relief occasion(s) is poorly constrained as a result of sparsity of ample topographic data, although it probably occurred in Ganymede’s center historical past (neither not too long ago, nor shortly after satellite tv for pc formation). The consistency between the timing and magnitude of the warmth fluxes derived right here and people inferred from different tectonic options suggests {that a} single occasion induced each Ganymede’s tectonic deformation and

  • City floor vitality fluxes primarily based on remotely-sensed information and micrometeorological measurements over the Kansai space, Japan

    NASA Astrophysics Information System (ADS)

    Sukeyasu, T.; Ueyama, M.; Ando, T.; Kosugi, Y.; Kominami, Y.

    2017-12-01

    The city warmth island is related to land cowl modifications and will increase in anthropogenic warmth fluxes. Clear understanding of the floor vitality finances at city space is a very powerful for evaluating the city warmth island. On this examine, we develop a mannequin primarily based on remotely-sensed information for the Kansai space in Japan and make clear temporal transitions and spatial distributions of the floor vitality flux from 2000 to 2016. The mannequin calculated the floor vitality fluxes primarily based on numerous satellite tv for pc and GIS merchandise. The mannequin used land floor temperature, floor emissivity, air temperature, albedo, downward shortwave radiation and land cowl/use kind from the average decision imaging spectroradiometer (MODIS) beneath cloud free skies from 2000 to 2016 over the Kansai space in Japan (34 to 35 ° N, 135 to 136 ° E). Web radiation was estimated by a radiation finances of upward/downward shortwave and longwave radiation. Smart warmth flux was estimated by a bulk aerodynamic methodology. Anthropogenic warmth flux was estimated by the stock information. Latent warmth flux was examined with residues of the vitality finances and parameterization of bulk switch coefficients. We validated the mannequin utilizing noticed fluxes from 5 eddy-covariance measurement websites: three city websites and two forested websites. The estimated web radiation roughly agreed with the observations, however the wise warmth flux had been underestimated. Primarily based on the modeled spatial distributions of the fluxes, the daytime web radiation within the forested space was bigger than these within the city space, owing to larger albedo and land floor temperatures within the city space than the forested space. The estimated anthropogenic warmth flux was excessive in the summertime and winter intervals as a result of will increase in energy-requirements.

  • Shock wave as a probe of flux-dimited thermal transport in laser-heated solids

    NASA Astrophysics Information System (ADS)

    Smith, Ok.; Forsman, A.; Chiu, G.

    1996-11-01

    Laser-generated shock waves in solids outcome from the ablation of the goal materials. The place radiation transport is negligible, the ablation course of is dominated by electron thermal conduction. This provides a chance to probe the diploma of transport inhibition (in contrast with classical warmth move) for steep temperature gradients in a dense plasma. Utilizing a 1-dimensional hydrodynamic code, we’ve examined the impact of flux-limited thermal conduction on the amplitude of the ensuing shock wave.

  • Defining High-of-Ambiance Flux Reference Degree for Earth Radiation Funds Research

    NASA Technical Reviews Server (NTRS)

    Loeb, N. G.; Kato, S.; Wielicki, B. A.

    2002-01-01

    To estimate the earth’s radiation finances on the prime of the ambiance (TOA) from satellite-measured radiances, it’s essential to account for the finite geometry of the earth and acknowledge that the earth is a stable physique surrounded by a translucent ambiance of finite thickness that attenuates photo voltaic radiation in a different way at completely different heights. Consequently, with the intention to account for all the mirrored photo voltaic and emitted thermal radiation from the planet by direct integration of satellite-measured radiances, the measurement viewing geometry should be outlined at a reference stage nicely above the earth s floor (e.g., 100 km). This ensures that each one radiation contributions, together with radiation escaping the planet alongside slant paths above the earth s tangent level, are accounted for. Through the use of a field-of- view (FOV) reference stage that’s too low (such because the floor reference stage), TOA fluxes for many scene sorts are systematically underestimated by 1-2 W/sq m. As well as, since TOA flux represents a move of radiant vitality per unit space, and varies with distance from the earth based on the inverse-square legislation, a reference stage can also be wanted to outline satellite-based TOA fluxes. From theoretical radiative switch calculations utilizing a mannequin that accounts for spherical geometry, the optimum reference stage for outlining TOA fluxes in radiation finances research for the earth is estimated to be roughly 20 km. At this reference stage, there isn’t any must explicitly account for horizontal transmission of photo voltaic radiation via the ambiance within the earth radiation finances calculation. On this context, subsequently, the 20-km reference stage corresponds to the efficient radiative prime of ambiance for the planet. Though the optimum flux reference stage relies upon barely on scene kind as a result of variations in efficient transmission of photo voltaic radiation with cloud top, the distinction in flux brought on by neglecting the scene-type dependence is lower than 0.1%. If an inappropriate

  • Water and sediment temperature dynamics in shallow tidal environments: The function of the warmth flux on the sediment-water interface

    NASA Astrophysics Information System (ADS)

    Pivato, M.; Carniello, L.; Gardner, J.; Silvestri, S.; Marani, M.

    2018-03-01

    Within the current examine, we examine the vitality flux on the sediment-water interface and the relevance of the warmth exchanged between water and sediment for the water temperature dynamics in shallow coastal environments. Water and sediment temperature information collected within the Venice lagoon present that, in shallow, temperate lagoons, temperature is uniform inside the water column, and enabled us to estimate the online warmth flux on the sediment-water interface. We modeled this flux because the sum of a conductive part and of the photo voltaic radiation reaching the underside, discovering the latter being negligible. We developed a “level” mannequin to explain the temperature dynamics of the sediment-water continuum pushed by vertical vitality switch. We utilized the mannequin contemplating situations characterised by negligible advection, acquiring passable outcomes. We discovered that the warmth trade between water and sediment is essential for describing sediment temperature however performs a minor function on the water temperature.

  • Results of Crack on Warmth Flux in Hypersonic Shock/Boundary-Layer Interplay

    NASA Astrophysics Information System (ADS)

    Ozawa, Hiroshi; Hanai, Katsuhisa; Kitamura, Keiichi; Mori, Koichi; Nakamura, Yoshiaki

    A small crack on physique floor led to a tragic accident in 2003, which is the Columbia accident. In the course of the shuttle’s re-entry, excessive temperature gasoline penetrated crack on modern of the left wing and melted the aluminum construction, lastly the Columbia blew up. Since early occasions, there are a lot of basic research about easy cavity-flow shaped on physique floor in hypersonic speeds. Nonetheless, an investigation of Shock/Boundary-Layer Interplay (SBLI) on crack has not been researched. For multistage area transportation automobile akin to TSTO, SBLI is an inevitable drawback, after which SBLI on crack turns into a important challenge for TSTO growth. On this examine, the results of crack, the place SBLI happens, had been investigated for TSTO hypersonic velocity (M∞ = 8.1). A sq. crack locates at SBLI level on the TSTO booster. Outcomes present {that a} crack and its depth strongly impact on peak warmth flux and aerodynamic interplay flow-field. Within the instances of shallow crack (d/C ≤ 0.10), there exist two excessive warmth flux areas on crack ground, which locates at a move reattachment area and a again finish wall of crack. On this case, a peak warmth flux at move reattachment area turns into about 2 occasions as massive because the stagnation level warmth flux, which worth turns into bigger in contrast with a peak warmth flux within the case of No-Crack TSTO. Whereas within the case of deep crack (d/C = 0.20), general warmth flux on crack ground decreases to under the stagnation level warmth flux. These outcomes present helpful information for a growth of TSTO thermal safety system (TPS) akin to thermal safety tile.

  • Circulation boiling warmth switch of R134a and R404A in a microfin tube at low mass fluxes and low warmth fluxes

    NASA Astrophysics Information System (ADS)

    Spindler, Klaus; Müller-Steinhagen, Hans

    2009-05-01

    An experimental investigation of move boiling warmth switch in a commercially out there microfin tube with 9.52 mm outer diameter has been carried out. The microfin tube is manufactured from copper with a complete fin variety of 55 and a helix angle of 15°. The fin top is 0.24 mm and the internal tube diameter at fin root is 8.95 mm. The check tube is 1 m lengthy and is electrically heated. The experiments have been carried out at saturation temperatures between 0 and -20°C. The mass flux was diversified between 25 and 150 kg/m2s, the warmth flux from 15,000 W/m2 right down to 1,000 W/m2. All measurements have been carried out at fixed inlet vapour high quality starting from 0.1 to 0.7. The measured warmth switch coefficients vary from 1,300 to fifteen,700 W/m2K for R134a and from 912 to 11,451 W/m2K for R404A. The imply warmth switch coefficient of R134a is in common 1.5 occasions larger than for R404A. The imply warmth switch coefficient has been in contrast with the correlations by Koyama et al. and by Kandlikar. The deviations are inside ±30% and ±15%, respectively. The affect of the mass flux on the warmth switch is most vital between 25 and 62.5 kg/m2s, the place the move sample modifications from stratified wavy move to nearly annular move. This move sample transition is shifted to decrease mass fluxes for the microfin tube in comparison with the sleek tube.

  • Essential Warmth Flux Phenomena at HighPressure & Low Mass Fluxes: NEUP Last Report Half I: Experiments

    SciTech Join

    Corradini, Michael; Wu, Qiao

    2015-04-30

    This report is a preliminary doc presenting an summary of the Essential Warmth Flux (CHF) phenomenon, the Excessive Strain Essential Warmth Flux facility (HPCHF), preliminary CHF information acquired, and the long run course of the analysis. The HPCHF facility has been designed and constructed to review CHF at excessive stress and low mass flux ranges in a rod bundle prototypical of conceptual Small Modular Reactor (SMR) designs. The rod bundle is comprised of 4 electrically heated rods in a 2×2 sq. rod bundle with a prototypic chopped-cosine axial energy profile and outfitted with thermocouples at numerous axial and circumferential positions embeddedmore » in every rod for CHF detection. Experimental check parameters for CHF detection vary from pressures of ~80 – 160 bar, mass fluxes of ~400 – 1500 kg/m2s, and inlet water subcooling from ~30 – 70°C. The preliminary information base established might be additional prolonged sooner or later together with comparisons to present CHF correlations, fashions, and so on. whose software ranges could also be relevant to the situations of SMRs.« much less

  • The 2-dimensional Stefan drawback with barely various warmth flux

    SciTech Join

    Gammon, J.; Howarth, J.A.

    1995-09-01

    The authors clear up the two-dimensional stefan drawback of solidification in a half-space, the place the warmth flux on the wall is a barely various perform of positioning alongside the wall, by means of a big Stefan quantity approximation (which seems to be equal to a small time answer), after which by the use of the Warmth Stability Integral Methodology, which is legitimate all the time, and which agrees with the big Stefan quantity answer for small occasions. A consultant answer is given for a selected type of the warmth flux perturbation.

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