Gas Phase Reynolds Number Research Articles

Experimental study on the mass transport characteristics of dilute iodine vapor from air to caustic soda solution in a packed column using different packing materials

It is imperative to minimize radioiodine release to the environment through gaseous emissions of spent fuel reprocessing facilities, thereby mitigating its potential impact on the general public. One effective and widely adopted strategy for achieving this objective is caustic scrubbing, a method that involves the absorption of molecular iodine from gaseous streams using caustic soda ( NaOH ) solution in a packed column. In-depth laboratory-scale experiments were conducted to ascertain the overall volumetric mass transfer coefficient K G a for the absorption of dilute iodine vapor from air into a caustic soda solution in a packed column and to establish optimum performance parameters for this process. The investigation yielded noteworthy findings: K G a increased proportionately to (Gas phase Reynolds number)1.0 at constant liquid flow rates across all types of packing tested. K G a displayed relative independence from liquid velocities for high and moderate NaOH concentrations. However, this coefficient varied proportionately to (Liquid phase velocity)0.26 to 0.42 at lower NaOH concentrations under conditions of high gas flow rates NaOH . As the height of the column increased, K G a was found to decrease slightly. The presence of NOx at an inlet concentration of 9000 ppm in the gaseous stream led to a reduction in the mass transfer coefficient of iodine, particularly at low NaOH concentrations. In summary, the study underscores the importance of caustic scrubbing as an effective means to minimize the release of radioiodine. The investigation’s results provide valuable insights into optimizing performance parameters for this process, contributing to enhanced environmental protection.

Two-phase pressure loss correlation for co-current flow in corrugated plate static mixers and structured packing

Co-current contacting of gas and liquid with a gas-continuous phase is a process with industrial relevance for natural gas processing, biogas upgrading, and carbon capture. Correlations that quantify two-phase, pressure losses under co-current flow conditions in corrugated geometries such as static mixers and structured packing at high gas-phase Reynolds numbers (ReG>105) are currently lacking. To fill this void, two-phase pressure losses in corrugated plate geometries under co-current flow conditions were measured at: 3,000<ReG<320,000 and 9<ReL<590. Our previously developed single-phase pressure loss correlation is extended to predict the results from this multiphase scenario by utilizing the separated flow modeling framework where each phase contributes to the pressure loss in an independent manner. The previously developed single-phase correlation matches the measurements with an overall Mean-Absolute Percentage Error (MAPE) of 20% at high ReG compared to a MAPE of 24 – 109% obtained from previous literature correlations. The new proposed correlation, employing the critical gas Reynolds number for the onset of liquid entrainment, reduced the MAPE to 7% for ReG>110,000 and 23% for ReG<110,000 compared to the dataset. A preliminary Computational Fluid Dynamics analysis shows that a simple, reflecting droplet boundary condition provides an adequate representation of the interfacial pressure loss effects for the range of conditions investigated in this study.

Hollow fiber nanoporous membrane contactors for evaporative heat exchange and desalination

The paper reports the performance of nanoporous polypropylene membrane contactors in water evaporative transfer processes, depending on membrane packing density, flow, and temperature conditions. The membrane evaporator's heat and mass transfer efficiency were evaluated in a wide range of partial pressure gradients and gas phase Reynolds numbers. A protocol for simple evaluation of evaporative heat flux to the heat exchange flux is introduced to reveal the efficiency of mass-to-heat transfer. It has been shown the evaporation efficiency significantly depends on gas flow conditions, increasing at Re ∼ 30 and exceeding 4.6 kg × m-2×h−1 (3.0 kW × m-2×h−1) at the temperature of inlet water of 60 °C. It is achieved by inducing convective flows in the gas phase, which enable the rise of effective heat transfer coefficient for membrane evaporator ∼250 W × m-2×K−1. The attained efficiency is confirmed to originate from heat extraction from the gaseous phase and the evaporation of water from the external surface of fibers. While exhibiting maximal heat flux the regime requires liquid phase penetration through the pores, leading to degradation of the membrane performance in desalination applications. To avoid penetration of ions thin (∼300 nm) graphene oxide coating was deposited onto the internal surface of the nanoporous evaporator, enabling to avoid liquid penetration through the pores and salts crystallization at the external surface, while exhibiting slightly lower performance of the membrane.

Experimental Study on Heat Transfer Characteristics of Two-Phase Flow in Square and Rectangular Channels

Two-phase flow in non-circular cross-section flow channels such as micro-heat sinks and micro-channel heat exchangers has received extensive attention due to its heat-enhancing properties. In this paper, under the boundary of constant heat flux, an experimental investigation of the heat transfer properties of gas–liquid two-phase flow in horizontal channels with cross-sections of 4 × 4 mm and 8 × 3 mm is carried out using air and water as working fluids. The effects of different inlet gas and liquid inlet Reynolds numbers on the wall temperature and Nusselt number are discussed. The results show that the effects of the liquid Reynolds number and the gas phase Reynolds number on the heat transfer coefficient of the square tube and the rectangular tube are different. Under the same gas–liquid Reynolds number, the Nusselt number of the gas–liquid two-phase flow in the square-section tube can be increased by 3.2 times compared with that in the single-phase flow, while the Nusselt number of the gas–liquid two-phase flow in the rectangular tubes can be increased by 1.87 times. The results of this paper provide a reference for the design of microchannel heat exchangers and the establishment of mathematical models for Taylor flow heat transfer in rectangular and square tubes.

Gas–liquid two-phase flow patterns and pressure drop of decaying swirling flow inside a horizontal pipe

Gas–liquid two phase swirling flow has been widely used in industry. Its flow pattern is fundamental to investigate the two-phase flow. In this paper, two-phase air–water flow patterns and pressure drop of decaying swirling flow generated by vane-type swirler inside a horizontal pipe have been systematically investigated by visualization experiment. The range of superficial gas phase Reynolds number is 17–23902, while superficial liquid phase Reynolds number is 12–37871, and gauge pressure is 0.003–0.17 MPa. The five typical flow patterns in a horizontal swirling flow were characterized based on flow visualizations and fluctuation characteristics of pressure drop signals. Then swirling flow regime map nearby the swirler outlet was proposed. As flow patterns altered along the streamwise direction due to swirl decay, flow pattern maps at different positions were proposed, which indicated the swirling flow patterns gradually transformed to non-swirling flow patterns. Finally, a new model to predict frictional pressure drop of air–water swirling flow inside a horizontal pipe containing vane-type swirler was proposed. This correlation performed well on predicting the frictional pressure drop.

Circumferential incoherent distribution of film thickness for multi-dimensional two-phase annular flow

Annular flow in rod bundle geometry is characterized by multi-dimensional properties in terms of two distinct length scales, rendering no consensus yet on an available model for predicting the circumferential incoherent distribution of film thickness. Current paper presents a semi-empirical but original correlation based on pertinent underlying physics. Gas phase Reynolds number is used to illustrate the gas–liquid interfacial shear-off mechanism. Liquid source term is scaled by the combination of void fraction and liquid volumetric flux. Circumferential shear stress produced by secondary flow is employed to denote mass transport in subchannel. Four available datasets including 189 data points are collected to develop and validate the proposed correlation from both cross-sectional and subchannel local regions perspectives. The majority of data can be correlated with the maximum relative error of ± 20.0%. Based upon the heuristic correlation, the circumferential incoherent distribution of film thickness is analyzed. The average film thickness on center rod increases slightly as the liquid velocity increased, since most of liquid phase migrates to corner region leading to a dramatically increase in film thickness on rod nearby duct wall. Two dependent factors are mainly responsible for the rod peripheral distribution of liquid thickness, in which the hydrodynamic effect dominates over the secondary flow factor, but the secondary flow makes the peripheral distribution of film thickness more uniform. Among the hydrodynamic parameters, both void fraction and gas velocity contribute to the thinning of the liquid film, but the increasing of liquid thickness along with rod periphery is attributed to the variation of subchannel characteristic length.

Drift-flux correlation for upward gas-liquid two-phase flow in vertical rod bundle flow channel

This paper has reviewed 17 available drift-flux correlations and collected 959 existing void fraction experimental data for air-water and steam-water two-phase flows in the vertical rod bundle flow channels. The performances of these drift-flux correlations have been evaluated with the collected experimental data. The evaluations conclude that the recently-developed drift-flux correlation of Schlegel and Hibiki gives the best predictions, and the drift-flux correlations of Clark et al. and Ye et al. can provide reasonable predictions for the collected experimental data. However, these drift-flux correlation series of Clark et al., Ye et al. and Schlegel and Hibiki are found to have the following three shortcomings. (1) Their distribution parameter correlation has ignored the flow regime and bubble behavior effects due to the different combinations of the non-dimensional superficial gas and liquid velocities at the same non-dimensional mixture volumetric flux under the high non-dimensional mixture volumetric flux conditions. (2) Their distribution parameter correlation has used the non-dimensional superficial gas and liquid velocities which cannot effectively reflect the pressure effect on the distribution parameter. (3) Their drift velocity correlation has ignored the drift velocity difference due to the flow regime transitions and has used the bubbly flow drift velocity correlation for all flow regimes, including the cap-bubbly, churn and annular flows. In view of these shortcomings, the present drift-flux correlation development adopts the segmented drift velocity correlations considering the features of bubbly, cap-bubbly, churn and annular flows in vertical rod bundle flow channel. The analysis for the experimental data of the asymptotic distribution parameter has shown that the asymptotic distribution parameter depends on the gas-phase Reynolds number with a feature that it linearly increases with gas-phase Reynolds number in the low gas-phase Reynolds number region, peaks at a critical gas-phase Reynolds number and exponentially decreases in the high gas-phase Reynolds number region under a certain liquid-phase Reynolds number flow conditions. This phenomenon is found to be caused by the formation and breakup processes of large-cap bubbles and their resultant intensive secondary flows corresponding to the flow regime transitions in the vertical rod bundle flow channel. So, a new distribution parameter correlation has been developed based on the gas- and liquid-phase Reynolds numbers reflecting the ratio of each phase inertial force to viscous force for the two-phase flows in vertical rod bundle flow channel. The newly-developed drift-flux correlation has been checked against various experimental data of air-water and steam-water two-phase flows in the rod bundle flow channel and a good agreement has been reached.

TIME-AVERAGED SPRAY ANALYSIS IN THE NEAR-FIELD REGION USING BROADBAND AND NARROWBAND X-RAY MEASUREMENTS

The characterization of a spray in the near-field region is challenging because of its high optical density in this region. X-ray based techniques, with weak scatter and strong penetration properties, can provide better characterization than optical assessment techniques in this region. In this work, the effects of various operating parameters on the optical depth (defined as the accumulated liquid thickness in the beam path times the X-ray attenuation coefficient) and spray profile of an atomizing spray in the near-field region are evaluated based on time-averaged X-ray analysis techniques. Controlling parameters in the spray structure include swirl ratio, liquid phase Reynolds number, and gas phase Reynolds number. Data from the broadband X-ray radiographs obtained using a tube source at Iowa State University and from focused beam measurements at the Advanced Photon Source at Argonne National Laboratory are compared. The X-ray tube source at Iowa State University was operated at two different energy levels, which reveals that the X-ray tube source energy influenced the magnitude of the optical depth but did not change the shape of the distribution. For the no swirl condition, gas flow rate and liquid flow rate had opposite effects on the spray profile, where the spray widens as the gas flow rate increases and narrows as the liquid flow rate increases. As the swirl ratio increases from 0 to 1, the spray widens and then narrows. The critical swirl ratio at which the spray reaches its widest spread differs at different flow conditions.

Analysis of droplet clustering in air-assist sprays using Voronoi tessellations

A comprehensive understanding on the dynamics of droplet clustering in sprays is important for a wide range of applications ranging from combustion engines to spray drying. Due to inherent flow inhomogeneity and air entrainment, the mechanism of dispersion of droplets in sprays is not the same as that in homogeneous and isotropic turbulence, which has been relatively well studied. The current research work aims to understand the physics of clustering of polydispersed water droplets in air-assist sprays. In particular, the focus is on studying the influence of local liquid mass loading on droplet clustering in the spray. For this purpose, the injector was operated for different inlet air and water flow rates. The droplet clusters as well as voids were uniquely characterized by the application of the Voronoi analysis on the spray images captured using the particle image velocimetry technique far downstream of the injector exit. The interferometric laser imaging for droplet sizing technique was used to measure the droplet size distribution. The droplet clustering in the spray was found to be a multi-scale process that spans over a wide range, from tens of the Kolmogorov scale up to a fraction of spray half-width. Similar normalized distributions of cluster and void areas for different cases suggested self-similarity of the clustering process. A new method for characterizing the length scale of droplet clusters was described. The average cluster length scale and the degree of clustering were found to strongly depend on local liquid mass fraction and gas phase Reynolds number. The radial evolution of droplet cluster statistics across the spray was also examined.

Fully coupled two-phase numerical model for falling film absorption in a vertical parallel plate channel

A two-phase numerical simulation is performed to investigate the absorption of water vapour into an aqueous lithium bromide solution inside a parallel plate vertical channel. The liquid film and vapour phase interactions and concurrent heat and mass interchange is modelled using a two-dimensional steady laminar flow model and a fully-coupled marching numerical scheme. The capability of this new model is examined by comparisons to the previous numerical results for a liquid film flowing over a cold wall. The numerical predictions are examined for the effect of the following operating parameters: the liquid film Reynolds number, the inlet mass fraction, and the wall temperature. New results are provided on the impact of the gas phase Reynolds number variation from 1000 to 3000 on the liquid film development along the channel.

Dynamics and mass transfer characteristics of CO2 absorption into MEA/[Bmim][BF4] aqueous solutions in a microchannel

Abstract The evolution of the size and velocity of CO2 bubble absorbed into MEA/[Bmim][BF4] aqueous solutions was in-line investigated by a high-speed camera. The coupling effect between the variation of volume and the velocity of bubbles was highlighted. According to the evolution of average mass transfer coefficient, the mass transfer performance in the whole flow process was studied. The results indicated that both the length and velocity of bubble decreased gradually in the flow process due to mass transfer. A linear correlation between the relative velocity (the ratio of average bubble velocity to two-phase superficial velocity) and the relative lost length (the ratio of the lost length to the initial length) was proposed. The increase in overall liquid-phase volumetric mass transfer coefficient (kLa) at higher gas flow rate could be ascribed to the shorter residence time and larger specific surface area. While the increase of kLa at higher liquid flow rate and MEA or [Bmim][BF4] concentration was resulted from intensified mass transfer. An empirical correlation of overall liquid-phase volumetric mass transfer coefficient was proposed taking the gas-phase Reynolds number, liquid-phase Reynolds number and Damkohler number into account.

Measurement and simulation of mass transfer and backmixing behavior in a gas-liquid helically coiled tubular reactor

Volumetric mass transfer coefficients (kLa) and Bodenstein numbers (Bo) for the elongated bubble flow regime in horizontal helically-coiled tube reactors are reported using two different measurement techniques (oxygen optodes, and optical observation of an oxygen-sensitive dye). Additionally, the gas-liquid mass transfer and the residence time behavior of the two-phase flow were described with a 3D Computational Fluid Dynamics (CFD) model, and also with a one-dimensional two-phase model. For this study, 16 cases involving different gas and liquid volumetric flow rates were employed to generate air-water flows through two helically coiled tubes with curvature ratios of δ1=0.093 and δ2=0.3, respectively. The superficial gas and liquid Reynolds numbers (Res,G and Res,L) and the gas hold-up (∊G) are varied from 494 to 2483, from 1456 to 2713, and from 0.46 to 0.81, respectively. The mass transfer measurements show an increasing gas-liquid mass transfer rate with increasing superficial velocity of the liquid-phase and Res,G. The Bodenstein number decreases with increasing gas-phase Reynolds number and increases with increasing superficial velocity of the liquid-phase. Correlations describing the mass transfer and backmixing behavior are proposed. The CFD results are in excellent agreement with the experimental data. With the 1D two-phase model it is possible to describe the residence time behavior of the two-phase flow through the helically coiled tube.

Axial dispersion in single and multiphase flows in coiled geometries: Radioactive particle tracking experiments

Liquid phase residence time distributions (RTD) are reported by employing a novel experimental method of tracking a radioactive tracer particle during single phase and two-phase (gas–liquid) flows through a horizontal helical coil. Liquid and gas phase Reynolds numbers (NRe, L and NRe, G) were varied in the ranges from 1061 to 23, 150 and 130 to 100,000 respectively. As part of this work, we tracked the entry and exit of the tracer particle in the coiled flow structure using an array of strategically placed scintillation detectors. From these experiments, it became possible to extract the residence time distribution (RTD) by enumeration of the trajectories of the tracer particle through the flow system. The investigations have resulted in explaining mixing performance for gas–liquid (two-phase) flow in coiled geometry, based on the trends in liquid phase Peclet number (NPe), over varying liquid and gas phase velocities.

Convective Condensation of Oxy-Coal Combustion Flue Gas of Laminar Fow in a Vertical Pipe

The problem of the oxy-fuel combustion flue gas condensation is the condensation of vapor in the presence of high concentration non-condensable gas. The vapor condensing at dew point temperature releases heat and diffuses on to the surface of the pipe through a non-condensable gas film. Thus it is treated as combined heat and mass transfer problem governed by mass, momentum and energy balance equations for the vaporgas mixture and diffusion equation for the vapor species. The flow of the falling condensate film is governed by the momentum and energy balance equations. The temperature at the gas-to-liquid interface, at which the condensation takes place, is estimated with the help of the heat balance and mass balance equations at the interface. The local values of the condensation Nusselt number, condensate Reynolds number, gasliquid interface temperature and pressure drop are estimated from the numerical results for different values of the system parameters at inlet, such as vapor component, temperature of vaporgas mixture, gas phase Reynolds number and total pressure. The thermodynamic calculations were made and analyzed using numerical calculation method under different conditions.

Experimental study on heat transfer and pressure drop characteristics of air–water two-phase flow with the effect of polyacrylamide additive in a horizontal circular tube

Experiments of air–water two phase heat transfer and frictional pressure drop without and with polyacrylamide (PAM) additive in a horizontal smooth circular tube were conducted. A PAM water solution with a concentration of 300ppm was used in the experiments. The test tube has an inside diameter of 40mm and an outside diameter of 48mm. Heat transfer tests were performed by cooling air–water flow inside the test tube through its wall using cooling water with a heat transfer length of 3m and two phase pressure drops were measured over a length of 3.1m. The liquid phase superficial velocity VLS=0.52, 1.02 and 1.46m/s and the gas phase superficial velocity VGS=1.66–4.9m/s. The average volume void faction β=0.532–0.904. The total mass flux G=5199–15,234kg/m2s and the gas phase Reynolds number ReG=3892–12,025. It shows that the air–water two phase pressure drops can be reduced from 31.9% to 54.7% while the two phase heat transfer coefficients can be reduced from 36.8% to 70.3% with the PAM additive. Furthermore, the effects of the PAM additive on the air–water two phase heat transfer and pressure drop characteristics have been analyzed. The observed flow patterns are all slug flows. New physical mechanisms of the two phase pressure drop and heat transfer reductions have been proposed.

Gas-phase mass-transfer measurements in a falling-film microreactor

The industrial-scale performance of gas–liquid reactors is difficult to control when very rapid or highly exothermic reactions are involved. Microstructured reactors offer new opportunities for these reactions by enabling precise heat management and accurate control of operating conditions. The present study examines experimentally the gas-phase mass-transfer characteristics of a reactor tool for the characterization of gas–liquid reactions: a falling-film microreactor. A well-known chemical test system, the absorption of sulfur dioxide SO 2 by sodium hydroxide NaOH is employed to determine the characteristics. The measurements of inlet and outlet concentrations in the gas phase enable the mass-transfer coefficient to be determined. The mass-transfer characteristics, in terms of dimensionless Sherwood number Sh G , are then related to the hydrodynamic characteristics of the gas phase, through the Reynolds number Re G , and the physico-chemical properties of the reactional system, through the Schmidt number Sc G . A strong dependence of dimensionless Sherwood number on gas-phase Reynolds number is observed, probably resulting from the specific features of the geometry of the gas-phase inlet.

Numerical simulation on dense phase pneumatic conveying of pulverized coal in horizontal pipe at high pressure

A kinetic–frictional model, which treats the kinetic and frictional stresses in an additive manner, was incorporated into the two fluid model based on the kinetic theory of granular flow to simulate three dimensional flow behaviors of dense phase pneumatic conveying of pulverized coal in horizontal pipe. The kinetic stress was modeled by the kinetic theory of granular flow, while the friction stress is from the combination of the normal frictional stress model proposed by Johnson and Jackson [1987. Frictional–collisional constitutive relations for granular materials, with application to plane shearing. Journal of Fluid Mechanics 176, 67–93] and the modeled frictional shear viscosity model proposed by Syamlal et al. [1993. MFIX documentation and theory guide, DOE/METC94/1004, NTIS/DE94000087. Electronically available from http://www.mfix.org], which was modified to fit experimental data. For the solid concentration and gas phase Reynolds number was high, the gas phase and particle phase were all treated as turbulent flow. The experiment was carried out to validate the prediction results by three kinds of measurement methods. The predicted pressure gradients were in good agreement with experimental data. The predicted solid concentration distribution at cross section agreed well with electrical capacitance tomography (ECT) image, and the effects of superficial velocity on solid concentration distribution were discussed. The formation and motion process of slug flow was demonstrated, which is similar to the visualization photographs by high speed video camera.

Convective Condensation of Vapor in Laminar Flow in a Vertical Parallel Plate Channel in the Presence of a High-Concentration Noncondensable Gas

The problem of laminar film condensation of a vapor from vapor-gas mixture in laminar flow in a vertical parallel plate channel is formulated theoretically. The flowing gas-vapor mixture contains a noncondensable gas in high concentration. An example of this case is the flow of humid air, in which air is present in high concentration. Vapor condenses at the dew point temperature corresponding to mass fraction of vapor in the gas-vapor mixture and the total pressure. The rate of condensation is controlled by the diffusion of the vapor through the noncondensable gas film. Thus the problem of convective condensation is treated as a combined problem of heat and mass transfer. The problem is governed by the mass, momentum and energy balance equations for the vapor-gas mixture flowing in a channel, and the diffusion equation for the vapor species. The flow of the falling film of condensate is governed by the momentum and energy balance equations for the condensate film. The boundary conditions for the gas phase and the condensate film are considered. The temperature at the gas-to-liquid interface is estimated by making use of the equations of heat and mass balance at the interface. The local condensation Nusselt number, condensation Reynolds number, and temperature at the gas-to-liquid interface are estimated from the numerical results for different values of the system parameters at the channel inlet, such as relative humidity, temperature of vapor-gas mixture, gas phase Reynolds number, and total pressure. The condensation heat transfer coefficients computed from the present theory are compared with the experimental data available in literature, and the agreement is found to be good. The present work is an extension of the earlier work, in which the problem of in-duct condensation of humid air in turbulent flow was solved theoretically. Humid air is considered as the gas-vapor mixture, since various physical and thermal properties have to be specified during the analysis.

Properties of disturbance waves in vertical annular two-phase flow

Disturbance waves play an important role in interfacial transfer of mass, momentum and energy in annular two-phase flow. In spite of their importance, majority of the experimental data available in literature on disturbance wave properties such as velocity, frequency, wavelength and amplitude are limited to near atmospheric conditions (Azzopardi, B.J., 1997. Drops in annular two-phase flow. International Journal of Multiphase Flow, 23, 1–53). In view of this, air–water annular flow experiments have been conducted at three pressure conditions (1.2, 4.0 and 5.8 bar) in a tubular test section having an inside diameter 9.4 mm. At each pressure condition liquid and gas phase flow rates are varied over a large range so that the effects of density ratio, liquid flow rate and gas flow rate on disturbance wave properties can be studied systematically. A liquid film thickness is measured by two flush mounted ring shaped conductance probes located 38.1 mm apart. Disturbance wave velocity, frequency, amplitude and wavelength are estimated from the liquid film thickness measurements by following the statistical analysis methods. Parametric trends in variations of disturbance wave properties are analyzed using the non-dimensional numbers; liquid phase Reynolds number ( Re f), gas phase Reynolds number ( Re g), Weber number ( We) and Strouhal number ( Sr). Finally, the existing correlations available for the prediction of disturbance wave velocity and frequency are analyzed and a new, improved correlation is proposed for the prediction of disturbance wave frequency. The new correlation satisfactorily predicted the current data and the data available in literature.

Convective condensation of vapor in the presence of a non-condensable gas of high concentration in laminar flow in a vertical pipe

The problem of laminar film condensation of vapor in the presence of high concentration non-condensable gas such as humid air flowing in a vertical pipe under laminar forced convection conditions is formulated theoretically. The vapor condensing at dew point temperature releases both sensible and latent heats and diffuses on to the surface of the pipe through a non-condensable gas film. Thus it is treated as combined heat and mass transfer problem governed by mass, momentum and energy balance equations for the vapor–gas mixture and diffusion equation for the vapor species. The flow of the falling condensate film is governed by the momentum and energy balance equations. The temperature at the gas-to-liquid interface, at which the condensation takes place, is estimated with the help of the heat balance and mass balance equations at the interface. The local and average values of the condensation Nusselt number, condensate Reynolds number, gas–liquid interface temperature and pressure drop are estimated from the numerical results for different values of the system parameters at inlet, such as relative humidity, temperature of vapor–gas mixture, gas phase Reynolds number and total pressure. The gas phase convection Nusselt and Sherwood numbers are also computed from numerical results. The predictions of the present study are compared with the experimental data available in literature, and the agreement is found to be reasonably good. An implicit pressure correction method developed by the authors is used in solving the momentum balance equation for the gas phase.