Turbulent Air Research Articles

Echofilter: A Deep Learning Segmention Model Improves the Automation, Standardization, and Timeliness for Post-Processing Echosounder Data in Tidal Energy Streams

Understanding the abundance and distribution of fish in tidal energy streams is important for assessing the risks presented by the introduction of tidal energy devices into the habitat. However, tidal current flows suitable for tidal energy development are often highly turbulent and entrain air into the water, complicating the interpretation of echosounder data. The portion of the water column contaminated by returns from entrained air must be excluded from data used for biological analyses. Application of a single algorithm to identify the depth-of-penetration of entrained air is insufficient for a boundary that is discontinuous, depth-dynamic, porous, and varies with tidal flow speed.Using a case study at a tidal energy demonstration site in the Bay of Fundy, we describe the development and application of deep machine learning models with a U-Net based architecture that produce a pronounced and substantial improvement in the automated detection of the extent to which entrained air has penetrated the water column.Our model, Echofilter, was found to be highly responsive to the dynamic range of turbulence conditions and sensitive to the fine-scale nuances in the boundary position, producing an entrained-air boundary line with an average error of 0.33 m on mobile downfacing and 0.5–1.0 m on stationary upfacing data, less than half that of existing algorithmic solutions. The model’s overall annotations had a high level of agreement with the human segmentation, with an intersection-over-union score of 99% for mobile downfacing recordings and 92–95% for stationary upfacing recordings. This resulted in a 50% reduction in the time required for manual edits when compared to the time required to manually edit the line placement produced by the currently available algorithms. Because of the improved initial automated placement, the implementation of the models permits an increase in the standardization and repeatability of line placement.

Numerical simulation of a Clear Air Turbulence (CAT) event over Northern India using WRF modeling system

Numerical simulation of a Clear Air Turbulence (CAT) event over Northern India using WRF modeling system

Influence of inlet boundary conditions on 3D steady RANS simulations of non-isothermal mechanical ventilation in a generic closure

Inlet boundary conditions at the supply opening play an important role in the accuracy and reliability of computational fluid dynamics (CFD) simulations for indoor airflow. A non-exhaustive overview of past CFD simulations of ventilation flow in generic enclosures indicates that uniform hypotheses of inlet boundary conditions are commonly used. However, due to thermal effects and a complex air supply system geometry, constant values of inlet airflow quantities can be insufficient for an accurate simulation of non-isothermal ventilation flow. In addition, this can lead to biased conclusions on the performance of turbulence models and other computational settings. To assess this issue, a well-documented experiment on non-isothermal mechanical ventilation with detailed information of inlet conditions from the literature is used in this study. Different turbulence models and inlet boundary conditions are validated, including seven steady Reynolds-averaged Navier-Stokes (RANS) models, six methods of imposing inlet air velocity, three methods of specifying air temperature, and a wide range of turbulence quantities. The parametric study demonstrates that in this particular case, i.e., cold air supply from a single round nozzle diffuser close to the ceiling, ω-based turbulence models perform better than the ε-based turbulence models. The impacts of different methods to specify inlet air temperature profile and turbulence quantities on the simulation results are not significant. However, if the inlet airflow direction is not taken into account appropriately, significant deviations are observed between CFD simulations and experimental data.

Turbulent flame image classification using Convolutional Neural Networks

Pockets of unburned material in turbulent premixed flames burning CH4, air, and CO2 were studied using OH Planar Laser-Induced Fluorescence (PLIF) images to improve current understanding. Such flames are ubiquitous in most natural gas air combustors running gas turbines with dry exhaust gas recirculation (EGR) for land-based power generation. Essential improvements continue in the characterization and understanding of turbulent flames with EGR particularly for transient events like ignition and extinction. Pockets and/or islands of unburned material within burned and unburned turbulent media are some of the features of these events. These features reduce the heat release rates and increase the carbon monoxide and hydrocarbons emissions. The present work involves Convolutional Neural Networks (CNN) based classification of PLIF images containing unburned pockets in three turbulent flames with 0%, 5%, and 10% CO2. The CNN model was constructed using three convolutional layers and two fully connected layers using dropout and weight decay. Accuracies of 94.2%, 92.3% and 89.2% were registered for the three flames, respectively. The present approach represents significant computational time savings with respect to conventional image processing methods.

Heat transfer augmentation through rectangular cross section duct with one corrugated surface: An experimental and numerical study

One of the techniques utilized to enhance the heat transfer rate within air ducts is creating turbulence inducing designs. In this work, turbulent air flow through a rectangular cross-sectional duct with one corrugated surface was experimentally and numerically investigated. Hydraulic and thermal behaviors of the system were evaluated at different Reynolds numbers. A test rig was constructed to experimentally investigate the performance. Also, a two-dimensional computational fluid dynamics simulation was performed using k-ε model to simulate fluid flow within the duct. The model was validated against previous results as well as the experimental results from this research. The computational and experimental findings were in reasonable agreement with a maximum error of less than 10%. The results showed that the existence of the corrugated surface considerably enhanced the heat transfer rate in all the studied cases, while slightly increasing the pressure drop. Consequently, a parametric study was performed to investigate the effect of different design parameters on the performance. The best performance was observed at a rib height to width ratio of 0.2, and groove length to width ratio of three, with a thermal enhancement factor of about 1.5. an empirical relation between Nusselt number and Reynolds number was established using the obtained results with a relative error value less than 8%. The study proved the value of using a corrugated surface as a means to increase heat transfer rate within rectangular air ducts.

Femtoliter-Droplet Mass Spectrometry Interface Utilizing Nanofluidics for Ultrasmall and High-Sensitivity Analysis.

In the fields of biology and medicine, comprehensive protein analysis at the single-cell level utilizing mass spectrometry (MS) with pL sample volumes and zmol to amol sensitivity is required. Our group has developed nanofluidic analytical pretreatment methods that exploit nanochannels for downsizing chemical unit operations to fL-pL volumes. In the field of analytical instruments, mass spectrometers have advanced to achieve ultrahigh sensitivity. However, a method to interface between fL-pL pretreatments and mass spectrometers without sample loss and dispersion is still challenging. In this study, we developed an MS interface utilizing nanofluidics to achieve high-sensitivity detection. After charging analyte molecules by an applied voltage through an electrode, the liquid sample was converted to fL droplets by a nanofluidic device. Considering the inertial force that acts on the droplets, the droplets were carried with a controlled trajectory, even in turbulent air flow, and injected into a mass spectrometer with 100% efficiency. A module for heat transfer was designed and constructed, by which all of the injected droplets were vaporized to produce gas-phase ions. The detection of caffeine ions was achieved at a limit of detection of 1.52 amol, which was 290 times higher than a conventional MS interface by electrospray ionization with sample dispersion combined with a similar mass spectrometer. Therefore, sensitivity that was 2 orders of magnitude higher could be realized due to the 100% sample injection rate. The present study provides a new methodology for the analysis of ultrasmall samples with high-sensitivity, such as protein molecules produced from a single cell.

EVALUATION OF INTERCEPTOR DESIGN TO REDUCE DRAG ON PLANING HULL

A planing hull is a high-speed craft with relatively complex hydrodynamic characteristics. An increase in speed can induce a significant change in trim angle with an increment in ship drag. One solution to reduce ship resistance is to use an interceptor. This research aimed to analyze the hydrodynamics of a planing hull vessel by applying an interceptor. The fundamental aspects reviewed included the analysis of drag, trim, heave, and lift force. The interceptor would be investigated on the basis of its integrated position at its height. This research also used the computational fluid dynamic (CFD) method in calm water conditions. All simulations were conducted with the same mesh structure, which allowed the performance evaluation of the interceptor in calculating turbulent air–water flow around the ship. Numerical calculations used the Reynolds-averaged Navier–Stokes (RANS) equation with the k–ε turbulence model to predict the turbulent flow. The vertical motion of the ship was modeled using dynamic fluid–body interaction (DFBI) in the fluid domain through an overset mesh technique. The numerical approach was compared with the experimental test results of Park et al. to ensure the accuracy of the test results. The interceptor was designed at the transition phase, which showed the highest trim angle followed by high drag. The interceptor would experience negative trim at high speeds; thus, it was not recommended. The research results indicated that the most effective use of the interceptor was at Froude number 0.87 close to the chine position with a height of 100%. This interceptor could reduce a maximum of 57% drag, 17% heave, 8.48% trim, and 0.12% lift force. The interceptor could increase excessive drag and trim at Froude numbers over 1.16. The interceptor proved to be remarkably useful in trim control and ship drag reduction, but selecting the wrong dimensions and positions of the interceptor could endanger the ship. This simulation was performed on Aragon-2; thus, the interceptor performance may possibly change if a different hull geometry is used.

Assessing the importance of mesoscale sea‐surface temperature variations for surface turbulent cooling of the Kuroshio Extension in wintertime

Western boundary currents are well known to exhibit a strong eddy field and meandering on subseasonal timescales and wavelengths of a few hundreds of kilometers. However, the extent to which the ocean mesoscale activity associated with these motions can enhance the turbulent air–sea heat flux averaged over a large spatial domain has not been fully characterized. This study aims to do so during the cold season using reanalysis data and simplified air–sea interaction models. The correlation between sea-surface height anomaly and the wintertime mean heat fluxes does not indicate any significant relations between eddy activity and large-scale surface heat flux in the Kuroshio Extension during winter over the 2003–2018 period. The results from simple models designed to isolate the contributions from the eddies suggest that the eddy enhancement of the heat flux via a rectified effect (a bit more anomalous cooling over a warm mesoscale feature than anomalous heating over a cold one) is small compared with the long-time, large-spatial scale mean in the reanalysis data, especially along the Kuroshio Extension. It is found larger north of it, where it can reach 5 W · $$ \cdotp $$ m − 2 $$ {}^{-2} $$ . Although different datasets might disagree about the level of energy of the sea-surface temperature field at the mesoscale, a simple scaling analysis gives confidence in the relatively small values of the rectified effect found here.

Investigation of Vortex Structure Modulation by Spume Droplets in the Marine Atmospheric Boundary Layer by Numerical Simulation

Direct numerical simulation (DNS) of a droplet-laden, turbulent Couette airflow over a waved water surface is performed modeling the marine atmospheric boundary (MABL) layer carrying idealized spume droplets. Both the instantaneous and mean flow properties, the characteristics of the vortex structures and the momentum exchange between air turbulence and waved water surface and droplet-mediated momentum transfer are investigated. A Eulerian–Lagrangian approach is employed in DNS where full, 3D Navier–Stokes equations for the carrier air are solved in a Eulerian frame, and the trajectories of individual droplets are simultaneously tracked in a Lagrangian frame. The impact of the droplets on the carrier air flow is modeled via a point force approximation. The droplets size is considered in the range of spume droplet sizes observed in MABL. Various water surface roughness and droplet injection scenarios are considered, and both instantaneous and phase-averaged flow fields, the Reynolds stresses and the eigenvalues of the local air velocity gradient tensor are evaluated in DNS. Numerical results show a strong dependence of the droplet-mediated airflow modification on-the-droplet injection mechanism. Droplets injected with the surrounding air velocity effectively mitigate the vortex structures by reducing their swirling strength and suppress the momentum flux from air turbulence to water surface by weakening both ejections and sweeping events, and thus accelerating the mean flow as compared to the droplet-free flow. On the other hand, droplets injected with the velocities of the Lagrangian particles of the water surface enhance both the swirling strength of the vortex structures and air-flow turbulent stresses and decelerate the mean wind. The results also show that these effects of droplet-mediated flow modification become less pronounced as the water surface wave steepness increases.

Impact of Breathing Pattern and Nebulization on Expelled Viral Content During Mechanical Ventilation Using an Ex Vivo Porcine Lung System.

Little is known about the fate of expelled viral particulates during the aerosolization of inhaled medications during mechanical ventilation. We hypothesized that breathing patterns that generate a greater degree of shear stress and turbulent air flow will produce a greater concentration of exhaled viral RNA with the presence of a nebulizer during mechanical ventilation. Eight ex vivo pig lungs were utilized as the physiological model. Each lung was dedicated to a specific breathing pattern that consisted of tidal breathing, respiratory distress, cough, and sneeze. Breath simulations were carried out through a commercial mechanical ventilator. Ninety mL of a bacteriophage stock at a concentration of 108 PFU/mL were introduced into the lungs during a 10-min sample collection session. The number of viral particles collected in exhalate was measured using quantitative polymerase chain reaction. The impact of breathing pattern on measured viruses was analyzed through two-way analysis of variance. The interaction effect between nebulization and breath pattern on exhaled viral quantity was not statistically significant P = .80, partial η2 = 0.167. The analysis of the main effects indicated that the effects of the breathing pattern and nebulization phase were not statistically significant P = .26, partial η2 = 0.519; P = .98, partial η2 = 0, respectively. There were no statistically significant differences among the breathing patterns related to measurable viral RNA. Coughing produced the most measurable increase in measured viral quantity during the nebulization phase and non-nebulization phase with a mean exhaled viral quantity (3.5 × 105 ng/μL [95% CI 1.6 × 105-5.5 × 105] and 2.7 × 105 ng/μL [95% CI 7.1 × 103-5.5 × 105], respectively). Tidal breathing with the presence of a nebulizer and respiratory distress without a nebulizer produced the lowest measured viral quantities (M = 1.1 × 105 ng/μL [95% CI -1.7 × 105 to 3.9 × 105]; M = 1.2 × 105 ng/μL [95% CI -1.6 × 105 to 4.0 × 105]). In this ex vivo porcine model, the introduction of a nebulizer did not increase the mean viral RNA captured throughout all of the breathing patterns.

Effect of large scale roughness of block ramps on dissolved oxygen efficiency in water

Abstract Block ramps are generally characterized by super critical flow over the ramps, and the presence of roughness lying on the surface of the block ramps induces excessive turbulence, which causes some turbulent energy dissipation and air entrainment. Aeration in a block ramp is caused by the intensity of turbulence created in the water flow by surface roughness of the block ramp and hydraulic jump downstream of block ramp. Macro or large-scale roughness like boulders, as a protruding element on surface of block ramp, could increase intensify turbulence and flow aeration along block ramps. This paper presents an experimental investigation of the dissolved oxygen efficiency in block ramps with slopes of 1:3, 1:5 and 1:7, on which large-scale granular materials with different arrangement patterns were glued. Comparison of results indicated that, for both free and ramp hydraulic jumps, the block ramps with a slope of 1:3 and large-scale roughness increase the dissolved oxygen efficiency almost 20% above that of the similar smooth block ramps. By reducing of the slope of block ramps to 1:5, the dissolved oxygen efficiency of the block ramps with large surface roughness became 3 and 19% for free and ramp hydraulic jumps, respectively. However, the block ramps with 1:7 slope had corresponding dissolved oxygen efficiency of 19 and 32%, respectively. Furthermore, installation of large scale roughness with the structured arrangement have better performance to increase dissolved oxygen (DO) in comparison with the interlocked large-scale roughness.

Analysis of thermally activated fluid-structure interaction for a morphing plate immersed in turbulent flow

In the framework of vehicle aerodynamics, new integrated systems can be developed based on shape memory metal alloys (SMAs) capability to perform surface morphing. Such systems can be exploited to create appendices containing active composites that change shape in response to variable thermal inputs, in relation to the desired aerodynamic behavior. The purpose of these systems is to offer benefits in terms of vehicle’s performance and fuel consumption rate. Even the design of the simplest geometry appendix, a finite horizontal plate aligned with a turbulent air flow, is nevertheless affected by three intertwined and nonlinear phenomena - namely the solid/fluid/thermal interactions. In order to approach the definition of appropriate design parameters, the space of operating variables must be explored by devising a numerical simulation encompassing the equation of structural motion and the energy and Reynolds Averaged Navier Stokes equations, complemented by a viable turbulence model. In this paper, a fully-coupled model encompassing all phenomena involved is tested by implementing a sensitivity analysis for a thermally activated morphing surface. Temperature, stress and velocity distributions are presented and discussed for a given geometry case. A new metrics leading to aerodynamic lift calculations is then proposed and demonstrated, that will simplify the preliminary design procedures.

Understanding Ozone Transport and Deposition within Indoor Surface Boundary Layers

Ozone-initiated oxidation reactions on indoor surfaces meaningfully alter the chemical composition of indoor air and human exposure to air toxins. Ozone mass transport within the indoor surface boundary layer plays a key role in ozone-surface reaction kinetics. However, limited information is available on detailed ozone transport dynamics near realistic, irregular indoor surfaces. This paper presents a research framework to study the underlying mechanisms of ozone reactions with realistic indoor surfaces based on microscope scanning of surface material and detailed Computational Fluid Dynamics (CFD) simulation. The study results show that indoor surface topography can meaningfully affect ozone mass transport within a surface boundary layer, thereby modulating near-surface ozone concentration gradient and surface uptake. The results also reveal that the effective indoor surface area available for ozone reaction varies with indoor air speed and turbulent air mixing within the boundary layer. The detailed dynamic behaviors of ozone reactions with realistic indoor surfaces provide insights into the implications of pollutant-surface interactions on indoor chemistry and air quality.

Diurnal Variation in Cloud and Precipitation Characteristics in Summer over the Tibetan Plateau and Sichuan Basin

The diurnal variation in precipitation and cloud parameters and their influencing factors during summer over the Tibetan Plateau (TP) and Sichuan Basin (SB) were investigated using the Hydro-Estimator satellite rainfall estimates, ground observations, and ERA5 dataset. The precipitation and cloud parameters show diurnal propagation over the SB during the mei-yu period in contrast to such parameters over the TP. The diurnal maximum precipitation from the Hydro-Estimator satellite and cloud ice and liquid water content (cloud LWC and IWC) from the ERA5 dataset are concentrated in the early evening, while their diurnal minimums manifest in the morning. Cloud LWC accounts for more than 60% of the total water during almost the entire diurnal cycle over the inner TP and SB during the mei-yu period. The IWC accounts for more than 60% of the total water in the late afternoon over the edge of the SB and TP. The cloud base height (CBH) above ground level (AGL), the lifting condensation level (LCL) AGL, and the zero degree level AGL are almost equal over the TP during the summer period. The zero degree level AGL over the SB is higher than that over the TP because the air temperature lapse rate over the TP is larger. The thickness of liquid water cloud over the SB is larger than that over the TP. The correlation analysis shows that the CBH AGL and LCL AGL over the TP are related to the dewpoint spread, but less so over the SB because of the stronger turbulence and lower air density over the TP than the SB. Convective available potential energy has a larger impact on precipitation over the TP than the SB. The cloud LWC makes a larger contribution to the precipitation over the SB than over the TP, which is related to the mean zonal wind and diurnal cycle of low-level winds. The precipitation at the edge of the TP and SB (i.e., the steep downstream slope) is largely influenced by the ice water contained within clouds owing to the convergence rising motion over the slopes.

Effects of design parameters on flow fields and heat transfer characteristics in semicircle oblique-finned corrugated

In this study, a new technique for heat transfer enhancement through the introduction and analysis of a semicircle oblique-finned corrugated has been studied numerically. Different design parameters are employed, including the vertical gap ratio (H) of 0.03, 0.04, and 0.05, the horizontal gap ratio (V) of 0.15, 0.20, and 0.25, as well as oblique-angle (θ) of 10°, 20°, and 40° are examined. Finite volume method (FVM) and the κ-ε model are used to simulate turbulent air flows inside the targeted channels at constant temperature conditions (T = 300 K) over Reynolds number between 10,000–50,000. The findings indicate that the employment of the new technique resulted in increased heat transfer and, as a consequence, increased thermal-hydraulic performance (PEC) via improved fluid mixing. The results also indicate that the effect of frictional loss has been used to influence the target system's overall performance in the direction of minimising the effect of heat transfer. The results show that a small vertical gap ratio and a high horizontal gap ratio have a greater effect on both heat transfer rate and PEC than others. Generally, the best PEC of 2.469 has been observed when V = 0.15, H = 0.05, and = 40 are used as design parameters. In terms of Nusselt number and friction factor, new correlations for the new model of semicircle oblique-finned corrugated are also reported.

МОДЕЛИРОВАНИЕ ПРОЦЕССОВ ТЕПЛООБМЕНА ВНУТРИ ГЕРМЕТИЧНОГО КОРПУСА БИНС В МУЛЬТИФИЗИЧНОЙ ПОСТАНОВКЕ В ANSYS CFX И SYSTEM COUPLING

The article presents a numerical simulation of non-stationary convective-conductive heattransfer of the strapdown inertial navigation system (SINS), developed in the JSC «CNIIAG».The numerical simulation is carried out in the ANSYS Mechanical. The aim of the study is a comprehensiveanalysis of heat exchange processes, which are characteristic to the device operation,including mutual spatial influence of thermal powers on each other, as well as on the block ofsensitive elements. The simulation of heat transfer inside the hermetic case of the SINS is carried out for critical operating conditions in a strongly and weakly coupled consideration with a comparisonof both approaches. ANSYS Mechanical, CFX and System Coupling simulation modulesare chosen for program implementation of each approach. The k-e model of air turbulence withimplicit consideration of the effect in the boundary layers and diffusion correction in shear flows ischosen for this approach. External heat exchange with ambient air is considered by setting convectiveboundary conditions on the external surfaces of the SINS, considering their orientation.To obtain numerical values of the heat transfer coefficients, the orientation of each surface inspace is taken into account by using the appropriate coefficient. The presence of irregularities onthe surfaces of the SINS in the contacts between solid components is considered by using the calculationof thermal resistances of the actual contact and intercontact layer. The simulation resultsof deformed state of SINS structural system, resulting from the action of a non-symmetric thermalfield, is presented. The analysis of the obtained graphs is carried out. Stiffness indicators of theSINS structural system is defined as angles of deviation of sensitivity axes caused by thermal deformations.The obtained results make it possible to evaluate the engineering solutions for thequality of heat removal from the elements of the PCBs, bypassing the sensitive elements of thedevice, adopted at the stage of product layout.

Resilience of radial carpet beams under propagation through indoor convective air turbulence

In this work, we investigate and compare propagation of Laguerre–Gaussian (LG) and the recently introduced radial carpet (RC) beams through an indoor convective air turbulence under weak to strong turbulence conditions. By determining the radial displacement of the intensity maxima over the donut ring of the LG beam, and tracing the radial coordinates of the main intensity spots of the RC beam, when the beams are propagating through the turbulence, we estimate the variance of the local displacements for both of the beams in the radial direction. It is shown that, under the same turbulence conditions, the RC beam experiences less disturbance and is more resilient to turbulence, especially when it has a complicated structure. The measured values of the image displacement variance for the RC beam are almost one order of magnitude smaller than the same parameter for the LG beam. In addition, for the LG beam, the symmetry of the beam is broken and in many places the intensity ring is even cut off. Although there are slight changes in the RC beams transverse intensity distribution, the number of the main intensity spots rarely changes. This feature makes the RC beam a good candidate for the transmission of information. We also show that a set of RC beams having different values of the main intensity spots (generated with different radial gratings having different spoke numbers) can be used as an orthogonal bases for free-space optical communication.

Optimization of hydrodynamic properties of structured grinding wheels based on combinatorial bionics

Undesirable hydrodynamic properties are inevitable in the traditional grinding process, which often provides a harsher lubrication environment. This paper introduces combinatorial bionics to optimize the hydrodynamic properties of grinding tools innovatively. Two bionic prototypes (phyllotaxis arrangement and fish scale) with special hydrodynamic properties are organically integrated to help design a combinatorial bionic grinding wheel (CBGW). The CBGW can more effectively inhibit the adverse effects of air turbulence on the grinding process and maintain a higher useful flow rate with a maximum improvement rate of 290.47%. This study enhances the effectiveness of grinding fluids from the perspective of grinding wheel structure and provides an excellent tribological basis for green and high-efficiency grinding.

Study of the linear measurement results in fog condition

The application of modern means of geodetic measurements largely depends on external disturbing influences. Factors such as a sharp temperature drop, air turbulence, its dustiness and gas contamination, negatively affect the results of geodetic measurements. This paper considers an example of modern geodetic equipment - a robotic total station TrimbleS9 equipped with an active reflective prism. With such equipment, it is possible to perform measurements in fog and dust conditions when solving certain applied tasks. The quality of the measurement results was evaluated in two cases - favorable conditions and in the presence of fog. It was found that in the presence of fog along the measured in, the value of the measured distance is significantly distorted and in our case reaches 5.0 mm. Such an impact on the measurement results will lead to significant errors in determining the coordinates.

Simulation of charging of PCM within a duct containing nanoparticles

AbstractWith the involvement of sinusoidal containers of phase change material (PCM) inside the duct, new configuration for the ventilation system has been achieved in the current paper. Mixture of TiO2 and RT25 was assumed as PCM, and the temperature of domain is fixed at 25°C at the start of the process. Owing to the radiation of the sun, air becomes warmer up to 35°C and with entering the air into the domain with Re = 6000, the melting process starts. The cold air at the outlet section can be utilized for ventilating the room. Homogeneous model for NEPCM and K‐ɛ approach for turbulent air flow has been incorporated. ANSYS FLUENT was applied for simulating this unsteady mechanism, and verification of the model was done according to previous experimental work. To control the air gap among tanks, the factor “b” was utilized and the influence of the fraction of titanium oxide (ϕ) was analyzed in results. As nano‐sized material has been added, more heat can be received to RT25 and the completed process can be reached in lower time. With considering the highest “b,” as nano‐sized material, the required time reduces from 20,672 to 19705 s. When ϕ = 0, growth of b leads to a reduction of time of about 42.57%.