Time of Wetness and Dew Formation: A Model of Atmospheric Heat Transfer

2009 ◽  
pp. 3-3-8 ◽  
Author(s):  
SW Dean ◽  
DB Reiser
Keyword(s):  
Heat Transfer ◽  
Dew Formation ◽  
Time Of Wetness ◽  
Atmospheric Heat

SLMB Modeling of the Full Spectrum Cumulative k-Distribution of H2O

2009 ◽  
Author(s):  
Fre´de´ric Andre´ ◽  
Rodolphe Vaillon
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Radiative Properties ◽  
Comprehensive Description ◽  
Full Spectrum ◽  
Reliable Technique ◽  
Gaseous Media ◽  
Energy Exchanges ◽  
Atmospheric Heat

Radiative heat transfer is significant in many applications involving energy exchanges in gaseous media, such as combustion in engines or furnaces, atmospheric heat balances,.. The Line-By-Line (LBL) approach is the most reliable technique to determine the radiative properties of gases but is rarely used in radiative transfer simulations due to the associated prohibitive computational requirements. Approximate models are favored for such calculations. A comprehensive description of these existing methodologies can be found in Refs. [1, 2].

scholarly journals Delineation of dew formation zones in Iran using long-term model simulations and cluster analysis

2021 ◽  
Vol 25 (9) ◽  
pp. 4719-4740
Author(s):  
Nahid Atashi ◽  
Dariush Rahimi ◽  
Victoria A. Sinclair ◽  
Martha A. Zaidan ◽  
Anton Rusanen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cluster Analysis ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Negative Trend ◽  
Balance Model ◽  
Formation Potential ◽  
Dew Formation ◽  
The Heat Transfer Coefficient

Abstract. Dew is a non-conventional source of water that has been gaining interest over the last two decades, especially in arid and semi-arid regions. In this study, we performed a long-term (1979–2018) energy balance model simulation to estimate dew formation potential in Iran aiming to identify dew formation zones and to investigate the impacts of long-term variation in meteorological parameters on dew formation. The annual average of dew occurrence in Iran was ∼102 d, with the lowest number of dewy days in summer (∼7 d) and the highest in winter (∼45 d). The average daily dew yield was in the range of 0.03–0.14 L m−2 and the maximum was in the range of 0.29–0.52 L m−2. Six dew formation zones were identified based on cluster analysis of the time series of the simulated dew yield. The distribution of dew formation zones in Iran was closely aligned with topography and sources of moisture. Therefore, the coastal zones in the north and south of Iran (i.e., Caspian Sea and Oman Sea), showed the highest dew formation potential, with 53 and 34 L m−2 yr−1, whereas the dry interior regions (i.e., central Iran and the Lut Desert), with the average of 12–18 L m−2 yr−1, had the lowest potential for dew formation. Dew yield estimation is very sensitive to the choice of the heat transfer coefficient. The uncertainty analysis of the heat transfer coefficient using eight different parameterizations revealed that the parameterization used in this study – the Richards (2004) formulation – gives estimates that are similar to the average of all methods and are neither much lower nor much higher than the majority of other parameterizations and the largest differences occur for the very low values of daily dew yield. Trend analysis results revealed a significant (p<0.05) negative trend in the yearly dew yield in most parts of Iran during the last 4 decades (1979–2018). Such a negative trend in dew formation is likely due to an increase in air temperature and a decrease in relative humidity and cloudiness over the 40 years.

Analytical Modeling of Mist Condensation by Natural Convection Over Inclined Flat Surfaces

2013 ◽  
Author(s):  
Mohammad Ali Fayazbakhsh ◽  
Majid Bahrami
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Analytical Model ◽  
Analytical Models ◽  
Formation Model ◽  
Humid Air ◽  
Cold Surface ◽  
Dew Formation ◽  
Simple Arrangement

Dew formation on a transparent surface creates a pattern that can cause blurred view over it. This fogging phenomenon should be avoided in many applications. Mist condensation of water on a cold surface exposed to humid air is studied in this work. In order to analyze the misting process, the fluid flow and heat transfer of humid air as well as the heat transfer across the solid surface are considered. A dew formation model is used to predict the shape and size of the droplets. Analytical models have been proposed to solve the heat and mass transfer for the simple arrangement of a vertical flat surface. The analytical model is then combined with the dew formation model to introduce an analytical model for mist condensation over vertical and inclined surfaces. Due to the proposed method, complex numerical calculations can be avoided for solving the heat and mass transfer equations.

Sign in / Sign up

Export Citation Format

Share Document