The emissivity of stainless steel in dairy plant thermal design

Baldwin, A.J.; Lovell-Smith, J.E.R.

doi:10.1016/0260-8774(92)90045-8

Cited by 11 publications

(6 citation statements)

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“…P s is the heating rate per meter of cable (in Wm -1 ); and B is the length of a cable segment (in m).S b ,S d and α sSt (in Wm -2 ) are the mean direct, diffuse and reflected short wave radiation fluxes, respectively, with α s being the surface albedo of the ground; and α f is the FO cable optic surface albedo.L ↓ +L ↑ (in Wm -2 ) are the average downward and upward longwave radiation fluxes, respectively; and is the FO cable surface emissivity. Based on the kind of stainless steel, emissivity values can range from 0.3 to 0.7 (Baldwin and Lovell-Smith (1992)); however, we assume a value of 0.5 (Madhusudana (2000)). σ is the Stefan-Boltzmann constant, 5.67 • 10 -8 (Wm -2 K -4 ); and σT 4 s is the outgoing longwave radiation of the fiber, i.e., L f iber ; T s and T f are the temperature (in K) of the heated cable segment and (unheated) reference segment (i.e., air temperature), respectively.…”

Section: Determination Of Wind Speedmentioning

confidence: 99%

Wind speed measurements using distributed fiber optics: a windtunnel study

Ramshorst

Coenders-Gerrits

Schilperoort

et al. 2019

Preprint

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Abstract. Near-surface wind speed is typically only measured by point observations. The Actively Heated Fiber-Optic (AHFO) technique, however, has the potential to provide high-resolution distributed observations of wind speeds, allowing for better characterization of fine-scale processes. Before AHFO can be widely used, its performance needs to be tested in a range of settings. In this work, experimental results on this novel observational wind-probing technique are presented. We utilized a controlled wind-tunnel setup to assess both the accuracy and the precision of AHFO under a range of operational conditions. The technique allows for wind speed characterization with a spatial resolution of 0.3 m on a 1 s time scale. The flow in the wind tunnel was varied in a controlled manner, such that the mean wind, ranged between 1 and 17 m/s. The AHFO measurements are compared to sonic anemometer measurements and show a high overall correlation (0.85–0.98). Both the precision and accuracy of the AHFO measurements were also greater than 95 %. We conclude that the AHFO has potential to be employed as an outdoor observational technique. It allows for characterization of spatially varying fields of mean wind in complex terrain, such as in canopy flows or in sloping terrain. In the future, the technique could be combined with conventional Distributed Temperature Sensing (DTS) for turbulent heat flux estimation in micrometeorological/hydrological applications.

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Section: Determination Of Wind Speedmentioning

confidence: 99%

Wind speed measurements using distributed fiber optics: a windtunnel study

Ramshorst

Coenders-Gerrits

Schilperoort

et al. 2019

Preprint

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show abstract

“…The wall temperature in the upper riser section decreased linearly with 100 K/m. At all other locations the wall temperature was fixed at 400 K. The initial solid and the inflow gas temperature were likewise at 400 K. The P 1 radiation model used Marshak's boundary condition [54] with an assumed wall emissivity of ¼ 0:8 [68]. The absorption and scattering coefficients of the particle suspension required by Eq.…”

Section: Simulation Of Csp Plantmentioning

confidence: 99%

A numerical investigation of gas-particle suspensions as heat transfer media for high-temperature concentrated solar power

Marti

Haselbacher

Steinfeld

2015

International Journal of Heat and Mass Transfer

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“…L ↓ and L ↑ (W m −2 ) are the average downward and upward longwave radiation fluxes, respectively, and is the FO cable surface emissivity. Based on the kind of stainless steel, emissivity values can range from 0.3 to 0.7 (Baldwin and Lovell-Smith, 1992); however, we assume a value of 0.5 (Madhusudana, 2000). σ is the Stefan-Boltzmann constant, 5.67 × 10 −8 (W m −2 K −4 ), and σ T 4 s is the outgoing longwave radiation of the fiber, i.e., L fiber ; h is the convective heat transfer coefficient (W m −2 K −1 ).…”

Section: Dts and Signal-to-noise Ratio Analysismentioning

confidence: 99%

“…As a result, the spatial distribution of field observations is limited. While it is possible to obtain distributed wind speed observations with remote sensing (e.g., Goodberlet et al, 1989;Bentamy et al, 2003), the spatial resolution is too low for many micrometeorological applications.…”

Section: Introductionmentioning

confidence: 99%

Revisiting wind speed measurements using actively heated fiber optics: a wind tunnel study

et al. 2020

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Abstract. Near-surface wind speed is typically only measured by point observations. The actively heated fiber-optic (AHFO) technique, however, has the potential to provide high-resolution distributed observations of wind speeds, allowing for better spatial characterization of fine-scale processes. Before AHFO can be widely used, its performance needs to be tested in a range of settings. In this work, experimental results on this novel observational wind-probing technique are presented. We utilized a controlled wind tunnel setup to assess both the accuracy and the precision of AHFO under a range of operational conditions (wind speed, angles of attack and temperature difference). The technique allows for wind speed characterization with a spatial resolution of 0.3 m on a 1 s timescale. The flow in the wind tunnel was varied in a controlled manner such that the mean wind ranged between 1 and 17 m s−1. The AHFO measurements are compared to sonic anemometer measurements and show a high coefficient of determination (0.92–0.96) for all individual angles, after correcting the AHFO measurements for the angle of attack. Both the precision and accuracy of the AHFO measurements were also greater than 95 % for all conditions. We conclude that AHFO has the potential to measure wind speed, and we present a method to help choose the heating settings of AHFO. AHFO allows for the characterization of spatially varying fields of mean wind. In the future, the technique could potentially be combined with conventional distributed temperature sensing (DTS) for sensible heat flux estimation in micrometeorological and hydrological applications.

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The emissivity of stainless steel in dairy plant thermal design

Cited by 11 publications

References 0 publications

Wind speed measurements using distributed fiber optics: a windtunnel study

Wind speed measurements using distributed fiber optics: a windtunnel study

A numerical investigation of gas-particle suspensions as heat transfer media for high-temperature concentrated solar power

Revisiting wind speed measurements using actively heated fiber optics: a wind tunnel study

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