A numerical study on effect of evaporation and condensation of water vapor on acoustic oscillations of a gas parcel with a Lagrangian approach in a thermoacoustic prime-mover

2017 ◽  
Vol 141 (5) ◽  
pp. 3887-3887
Author(s):  
Kyuichi Yasui ◽  
Noriya Izu
Keyword(s):  
Water Vapor ◽  
Numerical Study ◽  
Lagrangian Approach ◽  
Prime Mover ◽  
Acoustic Oscillations ◽  
Evaporation And Condensation

Un-Shocked High Amplitude Standing Waves in Wave-Shaped Resonators

2012 ◽  
Author(s):  
Dion Savio Antao ◽  
Bakhtier Farouk
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Ambient Pressure ◽  
Standing Waves ◽  
High Amplitude ◽  
Prime Mover ◽  
Non Linear ◽  
Resonator System ◽  
Cylindrical Resonators ◽  
Linear Nature

A numerical study of non-linear, high amplitude standing waves in non-cylindrical circular resonators is reported here. These waves are shock-less and can generate peak acoustic overpressures that can exceed the ambient pressure by three/four times its nominal value. A high fidelity compressible computational fluid dynamic model is used to simulate the phenomena in cylindrical and arbitrarily shaped axisymmetric resonators. A right circular cylinder and frustum of cone are the two geometries studied. The model is validated using past numerical and experimental results of standing waves in cylindrical resonators. The non-linear nature of the harmonic response of the frustum of cone resonator system is investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude non-linear oscillations demonstrated can be used as a prime mover in a variety of applications including thermoacoustic cryocooling.

INFLUENCE OF SONOCHEMISTRY ON SINGLE-BUBBLE SONOLUMINESCENCE

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1711-1714 ◽  
Author(s):  
LI YUAN ◽  
PING HE
Keyword(s):  
Water Vapor ◽  
Chemical Reactions ◽  
Electrostatic Interactions ◽  
Light Emission ◽  
Single Bubble ◽  
Evaporation And Condensation ◽  
Light Spectra ◽  
Weakly Ionized ◽  
Single Bubble Sonoluminescence ◽  
Low Degrees

Spherical oscillation of an acoustically levitated gas bubble in water was simulated numerically to elucidate the phenomenon of single-bubble sonoluminescence (SBSL). A refined hydro-chemical model was used, which took into account the processes of water vapor evaporation and condensation, mass diffusion, and chemical reactions. The numerical results show significant water vapor dissociations but rather low degrees of ionizations. A widely accepted weakly ionized gas model is then used to compute the light emission. Contrary to earlier predictions without chemical reactions, the present calculated light spectra are generally too small and the pulses are too short to fit to recent experimental results within stable SBSL range. To solve this contradiction, the electrostatic interactions of the ionized gases are included, which is shown to lower the ionization potentials of gas species in the bubble significantly.

scholarly journals A Numerical Study on the Energy Performance of a Novel Furnace With Acidic Gas Trap Absorbers

2020 ◽  
Author(s):  
Mingkan Zhang ◽  
Tim LaClair ◽  
Lingshi Wang ◽  
Xiaobing Liu ◽  
Zhiming Gao ◽  
...  
Keyword(s):  
Water Vapor ◽  
Heat Exchanger ◽  
Natural Gas ◽  
Liquid Water ◽  
High Efficiency ◽  
Numerical Study ◽  
Energy Performance ◽  
Cfd Model ◽  
Reactive Processing ◽  
Conventional Furnace

Abstract Natural gas furnaces are widely used in US residential and commercial building markets. An important issue for natural gas furnaces is serious corrosion and fouling problems caused by acidic gas, such as SOx. An advanced adsorption technology based on acidic gas trap (AGT) absorbers offers the possibility to remove SOx acidic gas from natural gas furnaces with high efficiency and low cost, thereby enabling the development of condensing furnaces without the use of expensive corrosion resistant materials in the heat exchanger. A three-dimensional (3D) computational fluid dynamics (CFD) model has been developed to evaluate the heat transfer performance of a furnace with AGT absorbers and to compare it with a baseline conventional furnace without the AGT. Moreover, an axisymmetric model has been built focusing on the absorbing process in the AGT. The baseline conventional furnace used for the study is a commercial condensing furnace (Rheem 92% AFUE 84,000 BTU Multi-Position Gas Furnace). This furnace was completely disassembled, and the dimensions of each part were carefully measured and used to build a detailed CFD model. A model representing the new furnace, incorporating the AGT absorbers, was developed by adding the AGT system to the conventional furnace model. For the CFD analysis, a mixture model was employed to characterize the heat and mass transfer during the condensing process in the furnace while considering three components — air, water vapor and liquid water. Condensation takes place in the condensing heat exchanger, where water vapor changes phase to liquid water, and the latent heat is thus used in the furnace for useful heating. The simulation results characterize the energy performance of both the conventional furnace and the novel furnace with AGT absorbers, as well as the reactive processing in the AGT. These results provide insightful guidance for the development of the AGT absorber-based furnace from the perspective of its energy performance and will be used to further optimize this novel furnace design.

scholarly journals Differential absorption lidar for water vapor isotopologues in the 1.98 µm spectral region: sensitivity analysis with respect to regional atmospheric variability

2021 ◽  
Vol 14 (10) ◽  
pp. 6675-6693
Author(s):  
Jonas Hamperl ◽  
Clément Capitaine ◽  
Jean-Baptiste Dherbecourt ◽  
Myriam Raybaut ◽  
Patrick Chazette ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Water Vapor ◽  
Spectral Region ◽  
Hydrological Cycle ◽  
Numerical Study ◽  
Lower Troposphere ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Relative Precision ◽  
Mixing Ratios

Abstract. Laser active remote sensing of tropospheric water vapor is a promising technology to complement passive observational means in order to enhance our understanding of processes governing the global hydrological cycle. In such a context, we investigate the potential of monitoring both water vapor H216O and its isotopologue HD16O using a differential absorption lidar (DIAL) allowing for ground-based remote measurements at high spatio-temporal resolution (150 m and 10 min) in the lower troposphere. This paper presents a sensitivity analysis and an error budget for a DIAL system under development which will operate in the 2 µm spectral region. Using a performance simulator, the sensitivity of the DIAL-retrieved mixing ratios to instrument-specific and environmental parameters is investigated. This numerical study uses different atmospheric conditions ranging from tropical to polar latitudes with realistic aerosol loads. Our simulations show that the measurement of the main isotopologue H216O is possible over the first 1.5 km of atmosphere with a relative precision in the water vapor mixing ratio of <1 % in a mid-latitude or tropical environment. For the measurement of HD16O mixing ratios under the same conditions, relative precision is found to be slightly lower but still sufficient for the retrieval of range-resolved isotopic ratios with precisions in δD of a few per mil. We also show that expected precisions vary by an order of magnitude between tropical and polar conditions, the latter giving rise to poorer sensitivity due to low water vapor content and low aerosol load. Such values have been obtained for a commercial InGaAs PIN photodiode, as well as for temporal and line-of-sight resolutions of 10 min and 150 m, respectively. Additionally, using vertical isotopologue profiles derived from a previous field campaign, precision estimates for the HD16O isotopic abundance are provided for that specific case.

Is the water vapor supersaturation distribution Gaussian?

2021 ◽  
Author(s):  
Subin Thomas ◽  
Prasanth Prabhakaran ◽  
Will Cantrell ◽  
Raymond A. Shaw
Keyword(s):  
Water Vapor ◽  
Large Eddy Simulation ◽  
Gaussian Distribution ◽  
Numerical Study ◽  
Mixing Model ◽  
Large Eddy Simulations ◽  
Mixing Processes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Vapor Supersaturation

AbstractWater vapor supersaturation in the atmosphere is produced in a variety of ways, including the lifting of a parcel or via isobaric mixing of parcels. However, irrespective of the mechanism of production, the water vapor supersaturation in the atmosphere has typically been modeled as a Gaussian distribution. In the current theoretical and numerical study, the nature of supersaturation produced by mixing processes is explored. The results from large eddy simulation and a Gaussian mixing model reveal the distribution of supersaturations produced by mixing to be negatively skewed. Further, the causes of skewness are explored using large eddy simulations (LES) and the Gaussian mixing model (GMM). The correlation in forcing of temperature and water vapor fields is recognized as playing a key role.

scholarly journals Water vapor in the pore space of snow

2001 ◽  
Vol 32 ◽  
pp. 51-58 ◽  
Author(s):  
Sergey A. Sokratov ◽  
Atsushi Sato ◽  
Yasushi Kamata
Keyword(s):  
Water Vapor ◽  
Snow Cover ◽  
Pore Space ◽  
Density Change ◽  
Crystal Surfaces ◽  
Evaporation And Condensation ◽  
Exchange Processes ◽  
Snow Crystal ◽  
Snow Crystals ◽  
Almost All

AbstractWater vapor in snow is responsible for two main processes connected to almost all studies where snow cover is involved: the snow-density change with time and snow recrystallization. Both processes are the result of a balance between evaporation and condensation on individual snow-crystal surfaces. However, such micro-scale mass balance has rarely been considered as a component of “macro-” heat and mass transfer in snow cover. The present work is an attempt to find a way of combining these two mass-exchange processes, as occurs in Nature. Density change and snow recrystallization rates are analyzed based on recently published temperature field observations around individual snow crystals, combined with experimental data on temperature distributions and recrystallization rates in snow under applied temperature gradients.

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