Influence of humidity on the convective heat transfer from small cylinders

Still, Martin; Venzke, Holger; Durst, F.; Melling, A.

doi:10.1007/s003480050161

Cited by 20 publications

(6 citation statements)

References 5 publications

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“…The strong inversion periods were marked with higher near-surface RH levels during the nighttime as shown in Figure 5b. Since moist air is characterized by higher heat transfer (Still et al, 1998), this could cause warming of the atmosphere above ground, which would result in reduced inversion layer thickness (Pasricha et al, 2003) and hence, could induce a positive feedback to lowering of H BL . The above observations were substantiated by the PBL simulations that showed lower nighttime H BL during strong inversion periods in contrast to the higher nighttime H BL during weak inversion periods (Figure 5c; see Text S1 in Supporting Information S1).…”

Section: Resultsmentioning

confidence: 99%

Planetary Boundary Layer Height Modulates Aerosol—Water Vapor Interactions During Winter in the Megacity of Delhi

et al. 2021

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The megacity of Delhi is located within the Indo-Gangetic Plain (IGP) and is one of the major sources of anthropogenic air pollution. It is a continental metropolitan area in a large valley south of the Himalayas, which causes the air masses to be constrained within the IGP (Figure 1). The air masses are vulnerable to high levels of particulate matter emissions from the megacity all year round (Bhandari et al., 2020), since it is a fast-growing urban agglomeration (Jain et al., 2016;Paul et al., 2021). During winter, a strong radiative thermal inversion causes the megacity to be enveloped by a shallow planetary boundary layer (PBL) in the nighttime, resulting in high relative humidity (RH) and aerosol mass burden (Arun et al., 2018;Murthy et al., 2020). The cold, humid and polluted conditions coupled with low wind speeds make the landlocked atmosphere conducive to fog and haze formation (Dhangar et al., 2021;Dumka et al., 2019;Ojha et al., 2020). Moreover, the aerosols in Delhi have enhanced water uptake ability as reported in the companion study by Gunthe et al. (2021), which can facilitate multiphase processes for formation of aerosols and thereby cause drastic visibility deterioration.

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Section: Resultsmentioning

confidence: 99%

Planetary Boundary Layer Height Modulates Aerosol—Water Vapor Interactions During Winter in the Megacity of Delhi

et al. 2021

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“…During impacts from projectiles, heat is generated in the target material. Humidity can enhance the heat transfer from materials into the surrounding air, influencing the erosion process, particularly with high impact rates [76]. Humidity is a problem for polymers, causing degradation through hydrolysis and water ingress.…”

Section: Humiditymentioning

confidence: 99%

Mapping of Meteorological Observations over the Island of Ireland to Enhance the Understanding and Prediction of Rain Erosion in Wind Turbine Blades

Nash¹,

Zekos²,

Stack³

2021

Energies

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Leading edge erosion is becoming increasingly important as wind turbine size and rainfall are predicted to increase. Understanding environmental conditions is key for laboratory testing, maintenance schedules and lifetime estimations to be improved, which in turn could reduce costs. This paper uses weather data in conjunction with a rain texture model and wind turbine RPM curve to predict and characterise rain erosion conditions across Ireland during rainfall events in terms of droplet size, temperature, humidity and chemical composition, as well as the relative erosivity, in terms of number of annual impacts and kinetic energy, as well as seasonal variations in these properties. Using a linear regression, the total annual kinetic energy, mean temperature and the mean humidity during impact are mapped geospatially. The results indicate that the west coast of Ireland and elevated regions are more erosive with higher kinetic energy. During rain events, northern regions tend to have lower temperatures and lower humidities and mountainous regions have lower temperatures and higher humidities. Irish rain has high levels of sea salt, and in recent years, only a slightly acidic pH. Most erosion likely occurs during winters with frequent rain infused with salt due to increased winds. After this analysis, it is concluded that Ireland’s largest wind park (Galway) is placed in a moderate-highly erosive environment and that RET protocols should be revisited.

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“…Nearly all coefficients can be determined by experiments on the corresponding material. But the thermal convection parameter modeling the rate of heat exchange between the surface of the material and environment depends on the material, surface roughness, and ambient state [ 75 ]. For example, moving air is known to extract more heat from the material than still air.…”

Section: Computational Implementation and Numerical Examplesmentioning

confidence: 99%

Thermo-mechano-chemical modeling and computation of thermosetting polymers used in post-installed fastening systems in concrete structures

Abali

Vorel

Wan‐Wendner

2020

Continuum Mech. Thermodyn.

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As thermoset polymers find frequent implementation in engineering design, their application in structural engineering is rather limited. One key reason relies on the ongoing curing process in typical applications such as post-installed adhesive anchors, joints by structural elements or surface-mounted laminates glued by adhesive polymers. Mechanochemistry including curing and aging under thermal as well as mechanical loading causes a multiphysics problem to be discussed. For restricting the variety of material models based on empirical observations, we aim at a thermodynamically sound strategy for modeling thermosets. By providing a careful analysis and clearly identifying the assumptions and simplifications, we present the general framework for modeling and computational implementation of thermo-mechano-chemical processes by using open-source codes.

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Influence of humidity on the convective heat transfer from small cylinders

Cited by 20 publications

References 5 publications

Planetary Boundary Layer Height Modulates Aerosol—Water Vapor Interactions During Winter in the Megacity of Delhi

Planetary Boundary Layer Height Modulates Aerosol—Water Vapor Interactions During Winter in the Megacity of Delhi

Mapping of Meteorological Observations over the Island of Ireland to Enhance the Understanding and Prediction of Rain Erosion in Wind Turbine Blades

Thermo-mechano-chemical modeling and computation of thermosetting polymers used in post-installed fastening systems in concrete structures

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