Air Flow Humidity Research Articles

Design and implementation of a sample environment for in situ moisture-dependent neutron dark-field imaging experiments

We present the design and construction of a custom neutron-transparent sample environment for in situ moisture-dependent neutron dark-field imaging (NDFI) experiments for the imaging facilities at the Paul Scherrer Institute (PSI), Villigen, Switzerland. This simple setup, combined with a moisture generator, features a continuous flow system to ensure a constant homogeneous flow of humid air to manipulate the sample’s moisture conditions at room temperature. To facilitate neutron dark-field imaging measurements, the chamber has a slim design to maximize the sample-detector distance scanning range. The chamber can maintain static or dynamic relative humidity conditions, allowing for humidity cycles. Beyond moisture-dependent studies, the system’s versatility allows its utilization in any type of gas stream-dependent study. This technical note details the engineering considerations, construction process, and validation of this sample environment.

UV‐A Light Dehydration: Kinetics of Microbial Inactivation Against Gram‐Positive and Gram‐Negative Bacteria

ABSTRACTUV‐A light exposure (365 nm, 4.6 ± 0.2 mW/cm2) was combined with low relative humidity (RH) air flow at room temperature to dehydrate sweet potatoes and reduce the population of inoculated bacteria. Control samples underwent dehydration with low RH air at room temperature and in the absence of UV‐A light to assess the importance of UV‐A light in the dehydration and microbial reduction processes. The UV‐A light‐dehydrated sweet potatoes resulted in the removal of approximately 97.2% ± 2% of the original mass of water, which was significantly higher than the control samples. Infrared spectroscopy analyses confirmed the preservation of the physical and chemical integrity of the UV‐A light‐dehydrated samples. Despite the absence of pretreatments for enzyme inactivation, the UV‐A light‐dehydrated sweet potato did not exhibit a decrease in luminosity or darkening of color often associated with dehydration. Additionally, the utilization of UV‐A light for the dehydration of sweet potatoes inoculated with ~6 log(CFU/gDry solids) of Escherichia coli K12 resulted in a 99.9% ± 0.1% or 3.1 ± 0.5 log(CFU/gDry solids) reduction with only a 92.2% ± 0.1% or 1.3 ± 0.5 log(CFU/gDry solids) reduction resulting from the control samples dehydrated without UV‐A exposure. In the case of samples inoculated with ~6 log(CFU/gDry solids) of Listeria innocua L2 there was a 99.2% ± 0.5% or 2.2 ± 0.3 log(CFU/gDry solids) reduction when UV‐A light was utilized and only a 60.9% ± 10.3% or 0.4 ± 0.1 log(CFU/gDry solids) reduction when samples were dehydrated in its absence.

Numerical Modelling of Phase Transformations of Water Droplets for Efficient Heat Recovery from Biofuel Flue Gas

The phase transformations of water droplets in the humid air flow for water injection into the flue gas in biofuel combustion technology under typical boundary conditions have been simulated. The numerical study was performed in two stages. The first one defines the influence of radiation on the thermal state of the water droplets and on the cycle of phase transformation modes. It is shown that the influence of radiation in a flue gas flow of 150℃→200℃ temperature on the thermal state of quantitatively injected water droplets is not significant, but it induces qualitative changes in the temperature field and influences phase transformations cycle of the droplets. In the second step, the cycling of the droplet phase transformation modes for water injection into the exhaust flue gas prior to a condensing economiser under typical boundary conditions was numerically investigated. It was justified that for efficient cooling and humidification of the flue gas before the condensing economiser it is necessary to inject water heated above the dew-point temperature by dispersing it into fine droplets.

Characterization and effectiveness of a miniaturized dielectric barrier discharge module for air disinfection

Effective inactivation of airborne pathogens is crucial for air quality control and the prevention of infectious diseases, especially in indoor human-living environments. In this work, a novel air disinfector based on surface dielectric barrier discharge (DBD) plasma was proposed. The discharge characteristics and the disinfection performance of the disinfector were investigated under different applied voltages, airflow rates, and humidity. The used DBD mainly works in the O3-dominant product mode with a discharge power of 1–3 W. The decreases in N2(C-B) emission intensity, ozone, discharge power, and discharge current with the increasing airflow humidity were observed. Humidity was found to be the most pronounced factor promoting the single-pass disinfection efficiency. The Z value reached 0.32 l/J for relative humidity of 70%–80%. Additionally, ozone and ions were found to play a minor role in plasma-mediated bacterial inactivation. The antibacterial effectiveness of the disinfector was also validated by 2-h circulating disinfection experiments. Efficiency was maintained above the disinfection level (>99.9%) after a 5000-h continuous running. Meanwhile, the ozone emission was below the standard limit requirements. The proposed air disinfector is promising for household use with the advantages of small size, bacterial inactivation capability, low ozone emission, and high perceptibility.

Influence of wall temperature on condensation rate in duct flow of humid air: a comprehensive computational study

Influence of wall temperature on condensation rate in duct flow of humid air: a comprehensive computational study

Influences of synoptic circulations on regional transport, local accumulation and chemical transformation for PM2.5 heavy pollution over Twain-Hu Basin, central China

The Twain-Hu Basin (THB), located in Central China, serves as a key juncture where the northerly “polluted” airflows of the East Asian winter monsoon meet the southerly warm and humid airflows. Using the T-PCA (T- Principal Component Analysis) objective synoptic pattern classification, FLEXPART-WRF (Flexible Particle Dispersion Model), and Random Forest model, we investigate the influences of synoptic circulations on regional transport, local accumulation, and chemical transformation of PM2.5 during heavy air pollution over the THB in January of 2015–2022. The results show that the transport-type synoptic pattern accounts for 65.16% of heavy PM2.5 pollution, indicating that regional transport of PM2.5 dominates the THB's heavy air pollution. The PM2.5/CO ratio is higher in the transport-type pattern and positively correlated with PM2.5 concentrations, reflecting a higher efficiency of chemical transformation to secondary PM2.5 in transport-type pollution compared with the accumulation-type pollution. Transport-type heavy PM2.5 pollution is predominantly influenced by upstream anomalous northerly and easterly airflows at the bottom of the high-pressure system, converging with the southern wind in the receptor area over the THB. Accumulation-type heavy pollution exhibits weak wind anomalies in central and eastern China under the control of a uniform pressure field. Furthermore, thermally-induced vertical circulations with sinking airflows in the middle and lower troposphere suppress the vertical air pollutant dispersions. The relative contributions of atmospheric factors for transport-type PM2.5 heavy pollution events are 38.0% for dynamical driver, 26.8% for thermal driver, and 35.1% for chemical transformation, while in accumulation-type, the contribution rates are 33.9%, 36.3%, and 29.7%, respectively. This study elucidates the influences of synoptic patterns on regional transport, local accumulation, and chemical transformation of PM2.5 for heavy air pollution, with implications for understanding changes of air quality in the receptor region of regional transport.

Air disinfection by nanosecond pulsed DBD plasma

Atmospheric pressure dielectric barrier discharge (DBD) plasma is an emerging and promising technique for air disinfection in public environments. Power supply is a crucial factor but it remains unclear about its impacts on the air disinfection performance of plasmas. In this work, a nanosecond (ns) pulsed power supply was applied to drive an in-duct grating-like DBD array to achieve fast single-pass air disinfection. The influence of pulse parameters and environmental factors on both the discharge characteristics and the single-pass bacterial inactivation efficiency were uncovered. At a close relative humidity (RH) level, the efficiency was dominated by the discharge power, namely, specific input energy could serve as the disinfection dose. A higher frequency, shorter pulse rising time, and suitable pulse width are preferred to obtain a higher Z value. The pulsed source was not notably superior to an alternating current source, or even worse at a low voltage frequency at the same discharge power. Airflow humidity was a predominant factor to improve the efficiency and a single-pass efficiency of ∼ 99% and a Z value of 2.2 L/J were achieved under an optimal RH of 50%–60%. This work provides fundamental knowledge of ns-pulsed DBD on discharge characteristics and air disinfection behaviors.

Investigation on Phase Transition and Collection Characteristics of Non-Spherical Ice Crystals with Eulerian and Lagrangian Methods

Ice crystal icing occurs in jet engine compressors, which can severely degrade jet engine performance. In this paper, two different numerical calculation methods, the Eulerian method and the Lagrangian method, were used to evaluate the dynamics, mass transfer, heat transfer, phase transition and trajectory of ice crystals. Then, we studied the effects of initial diameter, initial sphericity, initial temperature of ice crystal, and relative humidity of airflow on the phase transition and collection characteristics of ice crystal particles. Results indicate that the non-spherical characteristics of ice crystals have a significant impact on their impingement limits and collection characteristics. The collection coefficient of unmelted ice crystals is positively correlated with the initial particle diameter and sphericity, and negatively correlated with the initial particle temperature and the relative humidity of airflow. The melting rate of ice crystal particles on the impact surface increases exponentially with the initial diameter of the particles, linearly increases with the relative humidity of the airflow and initial temperature of the particles, and exponentially decreases with the sphericity of the particles.

Atmospheric air freshwater using TPMS compact heat exchangers

The technology of extracting freshwater from atmospheric air is currently accessible in tropical regions and is experiencing substantial growth in areas where freshwater scarcity is prevalent. Moreover, the water-cooling towers in power plants and district cooling chillers produce saturated air, which serves as a significant supply of humid air and consequently freshwater. Dehumidification is the necessary procedure for extracting water vapor from moist and saturated air in order to generate water. An efficient heat exchanger with a high ratio of surface area to volume is necessary to enhance the production of freshwater by condensing the water vapor present in the air. Triply periodic minimum surface (TPMS) structures possess intricate geometries, resulting in a high ratio of surface area to volume and intense turbulence. Consequently, these structures have exceptional heat transmission capabilities. The internal network structure of the TPMS enables the formation of a consistent layer of freshwater by direct interaction with humid airflow, resulting in a continuous flow. The objective of this study was to examine the structural architectures of TMPS that maximize the generation of freshwater from moist air under various humidity and flow conditions. This was achieved by employing accurate 3D computational fluid dynamics (CFD) models. The purpose of developing these models is to analyze the performance of the Gyroid-Solid TPMS structure and compare it to a vertical flat plate with the same surface area. Furthermore, the study examines the freshwater production efficiency of various TPMS designs (Gyroid-Solid, Gyroid-Sheet, and Diamond-Solid) with same porosity but varying levels of humidity in the air. The findings indicate that the Gyroid-Solid structure enhances the condensation flow rate by a threefold factor in comparison to the flat plate across different levels of humidity in the air. Furthermore, the findings indicated that Diamond-Solid exhibited superior performance when subjected to low airflow Reynolds numbers, whereas at high Reynolds numbers The Gyroid-Sheet exhibits the highest level of condensation among the three solid structures, surpassing the Diamond-Solid by 25% and the Gyroid-Solid by 65 %. The findings demonstrated a notable increase in the production of freshwater through the utilization of TPMS structures, thereby deepening our understanding of the crucial influence of geometry on the condensation process. Empirical formulae have been formulated to calculate the Nusselt number of atmospheric air for TPMS heat exchangers, taking into account various design and operational factors.

Numerical simulation of condensation flows of humid air in the high-pressure pneumatic pressure-reducing valve

The phenomenon of condensation and ice formation exists in the high-pressure air pressure-reducing valve (HPAPRV), severely impacting the pressure-reducing valve's aerodynamic performance and operational safety. The problem is that the phase change of humid air in a high-pressure supersonic flow is not fully understood. This study aims to elucidate the condensation effect in high-pressure supersonic flows and the influence of the inlet conditions on the behavior of the condensate flow. A computational humid air phase model has been developed to investigate the formation of massive droplets due to phase-change processes. The numerical approach is validated by comparing it with experimental data, demonstrating a strong correlation between the two. The condensation properties of humid air in HPAPRV are described in detail. The effects of the condensation properties of humid air at different inlet conditions are discussed in detail. The results show that an increase in the inlet pressure increases the level of supersaturation, which increases the nucleation rate and the droplet growth rate and promotes droplet production. Increasing the inlet temperature has little effect on the HPAPRV pressure-reducing performance and predicts the temperature range of water vapor condensation before and after the valve port. The liquid mass fraction can be reduced by 50.9% by increasing the inlet temperature by 30 K, from 283 K to 313 K. When the inlet temperature is below 283 K, water vapor condenses in front of the valve port. Decreasing the inlet humidity reduces the degree and extent of supersaturation, which decreases the nucleation rate and the liquid mass fraction. When low inlet humidity (under 10%), the condensation phenomenon did not almost occur inside the pressure-reducing valve.

PERFORMANCE OF HEAT PUMP BASED ON COMPOSITE ADSORBENT ‘SILICA GEL – CRYSTALLINE HYDRATE’

Performance of an adsorptive heat pump has been studied. The factors affecting the efficiency of its work have been analyzed. Operating parameters and efficiency of adsorptive heat pumps and adsorptive heat storage devices have been compared. An algorithm of calculating the basic operating characteristics of an adsorption heat pump in heat supply systems has been proposed. It involves calculating the mass transfer coefficient, final absolute humidity of the air flow passed though adsorbent layer, the water uptake or adsorption and the useful heat of adsorption and heat of condensation, determination of heat inputs for the operation of the device such as heating the adsorbent, case of the device, hydraulic circuit, the water in the tank and adsorbed water, heat of desorption and heat of evaporation, estimation the coefficient of energy performance. The evaluation criteria of the efficiency of adsorptive heat pumps and heat storage devices have been compared. It is shown that the operating parameters of the adsorptive heat pump and the adsorptive thermal energy storage device based on composite adsorbents ‘silica gel – sodium sulfate’ and ‘silica gel – sodium acetate’ are the same, i.e. airflow rate 0.08 - 0.1 m3/s and initial absolute humidity of airflow 0.03 – 0.04 kg/m3, which are corresponded with maximal efficiency of the device. The temperature of the humid air flow directed to the adsorbent layer is suggested to be set at 20 – 40 °C. The measures to increase the efficiency of the adsorptive heat pump are proposed. It is shown that ultrasonic air humidification allows to increase the coefficient of energy performance by almost 2 times compared to steam humidification. The obtained results can be used for developing energy-efficient heating systems of residential premises.

Climatic characteristics and main weather patterns of extreme precipitation in the middle Yangtze River valley

Abstract Based on the daily precipitation data and ERA5 reanalysis data of 40 years from 1981 to 2018 in the middle Yangtze River Valley (MYRV), the climatic characteristics of extreme precipitation are analyzed using statistical methods. The multivariate empirical orthogonal functions and spectral clustering methods are used to classify and synthesize the extreme precipitation weather. The results show that: (1) The spatial distribution of the extreme precipitation threshold is uneven due to the regional topography. The spatial distribution of the average precipitation and frequency of extreme precipitation days is characterized by the north-south antiphase distribution. (2) According to the main influencing systems, the 215 regional extreme precipitation days in the MYRV in the past 40 years can be classified into three types: southwest vortex type, typhoon type, and cold trough shear line type. (3) The southwest vortex type of extreme precipitation occurs in the deep warm and humid airflow in front of the southwest vortex trough, but the typhoon type has better thermal dynamic conditions, and the cold and warm airflow convergence of the cold trough shear line type is more obvious. The rainfall area of three types of extreme precipitation is the result of the synergistic effect of the system.

Reconstruction of the topographic evolution of the Nanling Range in South China and its implications for the East Asian Monsoon evolution

The East Asian monsoon is the largest periodic airflow on Earth and significantly affects the climate of East Asia. However, considerable controversy exists about the onset timing of the East Asian monsoon. As one of the southern barriers blocking the northward movement of the warm and humid airflow, the Nanling Range has likely recorded key topographic information related to the East Asian monsoon onset and development. We used apatite and zircon (UTh)/He data obtained from the Shaoguan–Guidong horizontal cross-section to reconstruct the two-dimensional (2-D) paleotopography of the Nanling Range on a long-term scale. Four vertical profiles in Shulouqiu, Erjian, Sanfenshi, and Leiwangdian were used to constrain the exhumation history of the Nanling Range. The result revealed the following: 1) The drainage divide began to move from south to north at 80 Ma. At 80 Ma, the south segment of the cross-section reached a peak elevation of ∼3.6 km. The asymmetric topography experienced a rapid elevation (and relief) decrease from 80 Ma to 40–30 Ma. The four vertical profiles also experienced increased cooling and high exhumation rates from 100 Ma to 40–30 Ma. 2) The south segment experienced more rapid exhumation than the north segment from 80 Ma to 40–30 Ma. The rapid exhumation of the south segment during the Late Cretaceous–Paleocene is probably related to the activity of the Nanxiong Fault, and the rapid exhumation of the south segment during the Eocene probably results from the onset of the East Asian Monsoon.

Interaction of water mists with bibulous filter media and hygroscopic particles in pressure drop jump of fibrous filter media

This study aims to quantitatively evaluate the impact of humid airflows (unsaturated and saturated airflows with water mists), water absorption by filters (wood cellulose and polyester fibre filter media) and hygroscopic loading dust (KCl and Al2O3 particles) on the pressure drop jump. Additionally, proposed methods to alleviate this tendency are known as the “wet blockage” of filters in practice. The experimental results demonstrated that the water content of the airflows mainly contributed to the pressure drop jump in the filters. Increasing the water content from 4.2 g/m3 to 11.3 g/m3 resulted in a fourfold decrease in the water-loading capacity of the tested filter medium. However, increasing the water absorption of the filters by a factor of three times caused a reduction in the water-loading capacity of approximately 42 mg/cm2 based on the self-defined parameter tc. Furthermore, the non-hygroscopic particles delayed the pressure drop jump, which is associated with the dust-holding capacity of filters.

NMR characterization of proton exchange membranes in controlled hygrometry conditions

NMR methods are highly sensitive to the state of water adsorbed in ionomer membranes for PEM fuel cells and electrolyzers. This study demonstrates the potential of NMR and MRI to reliably and accurately determine a wide range of water parameters such as proton chemical shift, transverse relaxation time, water content, and membrane thickness. Measurements are carried out in-situ in membranes in contact with humid air flows that are precisely controlled in terms of flow rate, temperature, and humidity. This precise management of the climatic conditions makes it possible to detect very small variations in the parameters measured, linked to the hydrothermal history of the membrane described in the literature. This history is erased when the membrane is humidity cycled several times. In addition, we demonstrate the use of this MRI imaging method to determine the resistance to water transfer across the membrane/humid air interface under steady-state conditions. Finally, we propose a refinement of the imaging method that reduces acquisition time by a factor of two, without degrading the 1D water content profile. This improvement gives us access to the study of transient hydration regimes typical of PEMFC and PEME operation.

Optimizing the use of light in supported TiO2 photocatalysts: Relevance of the shell thickness

Heterogeneous photocatalysts have attracted significant interest over the last few years. In this sense, improved photocatalytic properties for SiO2@TiO2 materials have been correlated with higher semiconductor's specific surface area and adsorption capability. However, the reported TiO2 shell optimizations did not consider the percentage of the photo-excited electron-hole (e−-h+) pairs occurring in the inaccessible surface of the TiO2 shell. The present study aimed to find the best TiO2 shell thickness for the optimal harvest of light. For this purpose, the sol–gel method was modified by applying a precise humid airflow to get a uniform deposition of titania on the surface of the SiO2 particles. As a result, photocatalysts with a robust and homogeneous TiO2 shell of different thicknesses (from 14 to 42 nm) with well-defined particle size for TiO2 crystals (ca. 12 nm) were obtained. The SiO2@TiO2 materials were extensively characterized. Finally, their photocatalytic activity was evaluated against methylene blue under irradiation by UVA light. Analysis of the results revealed that the most efficient photocatalyst has a TiO2 shell thickness of ca. 30 nm. Emission and photocurrent studies also agreed with the photocatalytic results suggesting a reduced e−-h+ recombination rate. Thereby, for the first time, the relevance of shell thickness in supported photocatalysts has been demonstrated.

Experimental analysis of drop size distribution and nucleation site density during dropwise condensation from humid air flow

Condensation of the water vapor present in the air is a heat and mass transfer process encountered in many applications as humid air dehumidification and water harvesting. Depending on the wettability characteristics of the surface, condensation can take place in filmwise mode or in dropwise mode with the formation of discrete liquid droplets over the condensing surface. While dropwise condensation (DWC) of pure steam was found to promote a considerable enhancement of the heat transfer compared to filmwise condensation, when dealing with humid air DWC more investigation is needed. Modeling of DWC from humid air requires the calculation of the heat flow rate through a single droplet and the determination of the drop-size distribution. The heat exchanged through a single droplet depends on the heat and mass transfer resistances, while the drop-size distribution is also affected by nucleation site density and droplets mobility. Therefore, to better understand the DWC phenomenon with humid air and for the validation of the models, it is necessary to measure the heat flux (total and latent), droplet population and nucleation site density. In the present work, condensation tests from humid air are performed over two square (40 mm x 40 mm) aluminum samples that display different wettability. The experimental apparatus consists of a closed air loop with two main components: the environmental chamber and the test chamber. The air is conditioned in the environmental chamber and then it flows inside the test section where the vapor present in the humid air is condensed over the vertical metallic sample. Two variable speed fans are used to circulate the air. The test section is designed for heat and mass transfer measurements and for simultaneous visualization of the condensation process. As a peculiar characteristic of the present experimental technique, all the test section assembly is suspended on a high precision balance allowing a precise measurement of the mass of condensate. The effect of surface wettability on the heat and mass transfer during DWC is investigated. Time-lapse videos of the condensation process are acquired at different magnifications. By using a homemade MATLAB® program for droplet detection, recorded images are analysed allowing the determination of both the drop size density distribution (small and large droplet population) and the nucleation sites density.

Integrated transparent surface acoustic wave technology for active de-fogging and icing protection on glass

There have been great concerns on poor visibility and hazardous issues due to fogging and ice/frost formation on glass surfaces of windshields, windows of vehicles/airplanes, and solar panels. Existing methods for their monitoring and removal include those active ones (such as using resistance heating) or passive ones (such as using surface icephobic treatments), which are not always applicable, effective or reliable. In this study, we proposed a novel strategy by implementing transparent thin film surface acoustic wave (SAW) devices by directly coating ZnO films onto glass substrate and studied their de-fogging, active anti-icing and de-icing mechanisms using the SAW technology. Effects of powers and wavelengths of SAW devices were investigated and influences of acousto-heating and surface hydrophobic treatments were evaluated. Results showed that de-fogging time was dramatically decreased with the increase of SAW powers when the thin film-based SAW devices were exposed to humid air flow for different durations. The icing accretion was significantly delayed under the applied SAW agitation, and SAW application has also effectively promoted de-icing on glass substrate, due to the interfacial nanoscale vibration and localized heating effect.

Diagnosing Potential Impacts of Tibetan Plateau Spring Soil Moisture Anomalies on Summer Precipitation and Floods in the Yangtze River Basin

AbstractSoil moisture as a key variable of land processes greatly influences the weather and climate. This study investigates the observed linkage between Tibetan Plateau (TP) spring soil moisture and summer precipitation and floods in the Yangtze River basin during 1988–2008 using satellite and in‐situ observations. A significant (p = 1%) proportion of interannual variations of summer precipitation (about 25%) in the Yangtze River basin can be attributed to spring TP soil moisture anomalies which show a dipole pattern. When spring soil moisture anomalies are positive (negative) over eastern (western) TP, there is more summer precipitation and consequently river discharge in the Yangtze River basin, or vice versa. The possible mechanisms can be explained from the perspectives of surface energy balance and atmospheric thermodynamics. More (less) spring soil moisture over the eastern (western) plateau enhances summer diabatic heating, which may be related to soil moisture memory. The enhanced summer diabatic heating stimulates vigorous ascending motions over TP, which diverge in the upper troposphere (200 hPa) and descend over the western Pacific. This is conducive to the enhancement and mutual proximity of the South Asian High (SAH) and the Western Pacific Subtropical High (WPSH). As a result, the warm and humid air flows from the Bay of Bengal and the western Pacific and the cold and dry air flows from the boreal continent converge in the Yangtze River basin, causing excessive summer precipitation. Therefore, TP spring soil moisture can be considered a seasonal predictor of summer precipitation and possible subsequent floods in the Yangtze River basin.

Metrological studies of a reference installation for reproducing the mass flow of humid air

The relevance of the development and metrological studies of reference installations when working in a humid gas medium is considered. The concept of creating a reference installation for reproducing the mass flow of humid air is outlined. An algorithm for the operation of a reference installation has been developed, which provides for the generation of water vapour as a component of the gas flow. Based on the algorithm and operation features of a reference installation, a list of the considered type A uncertainties, which relate to the estimation of the air volume measured by a reference meter, duration of the control volume reproduction, mass of generated water vapour during the period of reproduction of the volume, and relative humidity of the ambient air, was formulated. Type B uncertainties are considered, which are determined by metrological characteristics of the used measuring equipment: reference gas meter, chronometer, hygrometer, manometer, thermometer, and instruments for measuring the mass of generated moisture. Algorithms for evaluating the standard uncertainty by using the standard reference data are given: pressure and density of saturated water vapours, and air density under standard conditions. The formula and algorithm for its metrological evaluation based on the uncertainty theory for determining the compressibility coefficient of the ambient air used during the operation of the installation, taking into account its relative humidity, are also presented. The expressions for evaluating the combined and extended uncertainties of the developed installation are given.
 The developed model relates to the mass measurement of wet gas and allows assessing the influence of operating conditions of the installation on the indications of the mass flow measuring equipment of various operating principles, for example, thermo-anemometric, ultrasonic.
 The developed metrological model can be used to estimate metrological characteristics of reference installations operating in different types of gaseous medium, including natural gas.