Effect Of Flow Rate Research Articles

Effect of flowrate on the size segregation of magnetic nanoparticles by using continuous flow magnetic separator

Magnetic Nanoparticles (MNPs) possess significant potential across various sectors due to their versatility. However, specific MNP sizes are crucial for effective utilization. Traditional methods for synthesizing monodispersed MNPs are often expensive, complex, or environmentally harmful. This study proposes the effect of flow rate on the size segregation of MNPs using a continuous flow low gradient magnetic separator (CFLGMS). To produce MNPs that are monodispersed, firstly, MNPs undergo functionalization with the polyelectrolyte, poly (sodium 4-styrene sulfonate) (PSS), to enhance colloidal stability. Employing PSS molecules as splicing agents effectively inhibits MNP aggregation. To further enhance the monodispersity of MNPs, continuous flow is facilitated by configuring three separator columns in series, with permanent magnets (NdFeB) attached to the sides. As larger MNPs exhibit stronger magnetic field attraction, resulting in their capture by magnets first, followed by smaller MNPs, and finally the smallest ones. Consequently, MNPs captured in Column 1 possess the largest size, while those in Column 3 have the smallest size. Additionally, this paper investigates the impact of solution flowrate on size segregation efficiency. By varying the solution flow rate (10 mL/min, 15 mL/min, and 20 mL/min), it is found that the performance of the size segregation system is higher under the lower solution flowrate.

Innovative application of Myrrh resin (Commiphora molmol) as new biocarrier for immobilization of bacterial cells mix for biodegradation of anionic surfactant in airlift bioreactor: Assessment of hydrodynamic parameters

Immobilization of bacterial cells proved to offer remarkable advantages over conventional biotreatment systems using free cells. In this study, Myrrh resin (MR) was utilized as a new nonconventional biocarrier for bacterial cells immobilization used for aerobic degradation of sodium dodecyl sulphate (SDS) in a lab-scale airlift bioreactor (ALBR). Biodegradation of SDS was individually accomplished in four different actual SDS loaded-wastewaters including municipal wastewater (MWW), detergents industry wastewater (DWW), laundry wastewater (LWW) and carwash garage wastewater (CWW). Effects of air and wastewater flowrates on SDS biodegradation rate were determined in the ALBR. The results indicated that by increasing the flowrate of air from 1.5 to 2.5 L/min, the SDS biodegradation increased, whereby, it decreased by increasing the liquid flowrate from 1.2 to 2 mL/min. The power input in the ALBR increased from 0.09 to 0.72 W, as the air flowrate into the riser increased from 1.5 to 2.5 L/min. Experimental data of the overall gas holdup fitted well with the predicted data obtained by Chisti correlation with coefficient of determination (R 2) equal 0.939 and sum-squared error (SSE) of 6.2 × 10−4. The liquid circulation velocity model obtained by Chisti fitted well the experimental value with (R 2) of 0.950.

Integration of CFD analysis and artificial neural networks for estimation of erosion rate in oil and gas pipelines

Transporting oil and gas via pipelines has been creating countless challenges; sand particles deposit and erode the pipelines wall. Generally, conventional erosion rate prediction models are conservative due to numerous generalizations and theories. Finite Element Analysis via computational fluid dynamics (CFD) approach has proven to be useful to solve sand deposition problems and to estimate the eroded pipe due to its capability to precisely determine erosion deficiencies and make predictions with great precision. In this study, a CFD model was developed to calculate sand erosion rates in a 2-inch, 90° elbow pipe. Effects of particle sizes, sand flowrates, fluids velocities and pipe diameters on erosion rates were studied. The model was validated against literature data, and it was then used to generate data via sensitivity analysis simulations. The data became the basis for developing artificial neural network (ANN) models, which were then deployed in the environment of a process simulation software called Symmetry. Based on this approach, a variety of pipelines can be modelled, and maximum erosion rates of pipelines are calculated using deployed ANN models. Hence, a comprehensive study on the fluid flow dynamics and erosion rates of the pipelines can be evaluated simultaneously.

Gasification of olive tree pruning in a rotary kiln reactor integrated with radio frequency plasma torch

Olive tree pruning pellets are gasified by air in a bench-scale rotary kiln gasifier integrated with a radio frequency plasm torch. For the first time the technical suitability of the proposed configuration is herewith assessed. The effect of biomass flowrate (190–900 g/h), equivalence ratio (0.15–0.30), gasification temperature (650–900 °C), on syngas composition and yield is investigated. By increasing the biomass flowrate, from 190 to 900 g/h at 800 °C, both hydrogen and carbon monoxide mole fractions decreases, while the carbon dioxide mole fraction increase, with a drop in CGE from 76 % to 26 % increasing the biomass flowrate from 190 to 900 g/h at 800 °C. Higher temperature has a beneficial effect on syngas composition and CGE that increase from 20 % to about 64 % by increasing the temperature from 650 to 900 °C at a biomass flowrate of 450 g/h. The tar content shows a decreasing trend with equivalence ratio and temperature while it shows an increasing trend with biomass flowrate. The integration of the radio frequency plasma torch treatment of raw gas produced at 650 °C, with equivalence ratio of 0.15 and a biomass flowrate of 450 g/h shows good performance in hydrocarbons conversion, with a significant increase in terms of hydrogen yield. The H2/CO molar ratio increased by 104 % due to reforming reactions generating H2 and CO. A reduction of CO2 is also observed. With the RFPT treatment, gravimetric tar content was lower than the limit of detection while the concentration of light aromatics, i.e. benzene and toluene, decreases from 8.3 g/Nm3 to 2.2 g/ Nm3. The proposed post-gasification technology is worthy of further investigation for hydrogen production from biomass.

The efficiency of portable air cleaners in reducing cross-exposure through respiratory aerosols: Effects of flowrate, location, and unit type

This study evaluates the efficacy of portable air cleaners (PACs) in a controlled climate chamber that simulates an office environment, assessing their impact on respiratory particle transmission between two thermal manikins (representing an infected and an exposed individual) as well as on the noise level in the chamber. The study explores three types of PAC, namely floor-type (PAC1), table (PAC2) and personalized (PAC3) in various locations and operation modes. The particles were generated using an aerosol generator and introduced into the infected manikin's exhalation; the particle concentration at the exposed manikin's breathing zone (BZ) was measured using an aerodynamic particle sizer. The results showed that the PAC2, operating at a flow rate of 97 m³/h, significantly reduced the intake fraction (IF) by over 90 % within the first hour, proving to be the most effective in minimizing cross-exposure risks while maintaining sound levels within the acceptable limits for office rooms. In contrast, PAC3, with a lower flow rate of 13 m³/h, reduced IF by only 21.6 % after 60 min. The result also showed that settings with higher flow rates (higher than 134 m3/h) resulted in noise levels above the maximum allowable for office spaces for all tested PACs. Additionally, prolonged operation did not further decrease IF significantly after reaching optimal reduction levels within 30–60 min, depending on the PAC type and settings. Further, the study showed that strategic placement away from direct alignment with occupants' BZ is recommended to optimize aerosol removal and noise management.

Impact of gas flowrate on performance of chemiresistive NO2 sensors

This paper investigates in-depth the practical implications and the underlying mechanism of the effect of gas flowrate on the sensing performances of chemiresistive sensors. Three different types of 2D sensing layers were chosen for this study − metal oxide (ZnO, synthesized using hydrothermal method), organic polymer (tetrazine, synthesized using modified Pinner method), and transition metal dichalcogenide (WS2, synthesized using liquid exfoliation technique). The 2D morphologies of all the materials were confirmed using a field emission scanning electron microscope. These materials have different crystallographic structures, bandgaps, and functional groups. Yet, the response of all of them for 2–10 ppm NO2 was found to increase with increasing total flowrates when tested at 100, 500, and 1000 sccm. The response of ZnO varied from 6 to 46 %, 93 to 521 %, and 117 to 1416 %, while that of 2D tetrazine was found to vary from − 5.3 to − 13.9 %, −8.1 to − 26.5 %, and − 8.9 to − 34.2 %, and for WS2, the response ranged from 0 %, −0.8 to − 5.2 %, and − 2 to − 12.2 % for 2 – 10 ppm NO2 at 100, 500, and 1000 sccm flowrates, respectively. The response times and the recovery times of all the materials, too, exhibited the effect of gas flowrate.

Heat and Mass Transfer Model for a Counter-Flow Moving Packed-Bed Oxidation Reactor/Heat Exchanger

Abstract Particle-based thermochemical energy storage (TCES) through metal oxide redox cycling is advantageous compared to traditional sensible and latent heat storage (SHS and LHS) due to its higher operating temperature and energy density, and the capability for long-duration storage. However, overall system performance also depends on the efficiency of the particle-to-working fluid heat exchangers (HXs). Moving packed-bed particle-to-supercritical CO2 (sCO2) HXs have been extensively studied in SHS systems. Integrating the oxidation reactor (OR) for discharging with a particle-to-sCO2 HX is a natural choice, for which detailed analysis is needed for OR/HX design and operation. In this work, a 2D continuum heat and mass transfer model coupling transport phenomena and reaction kinetics is developed for a shell-and-plate moving-bed OR/HX. For the baseline design, the model predicted ∼75% particle bed extent of oxidation at the channel exit, yielding a total heat transfer rate of 16.71 kW for 1.0 m2 heat transfer area per channel, while the same design with inert particles (SHS only) gives only 4.62 kW. A parametric study was also conducted to evaluate the effects of particle, air, and sCO2 flowrates, channel height and width, and average particle diameters. It is found that the respective heat transfer rate and sCO2 outlet temperature can approach ∼25 kW and >1000 °C for optimized designs for the OR/HX. The present model will be valuable for further OR/HX design, scale-up, and optimization of operating conditions.

MODEL FOR ESTIMATING SKIN FACTOR OF PERFORATED LINERS IN HORIZONTAL WELLS

One notable completion method for enhancing productivity in horizontal wells is the use of perforated liners. However, a major challenge common to horizontally completed wells is to perform an accurate measurement of the skin factor. Perforated liners can create several hurdles, capable of negatively affecting productivity, such as partial plugging, flow convergence, and turbulence. This paper introduces a new analytical skin factor model which incorporates distance between perforations and explains the effects of flowrate on skin for various parameters like perforation radius, wellbore radius, and distance between perforations for perforated liner completions. Results show that skin factor is directly proportional to flow rate and distance between perforations, however, they are inversely proportional to wellbore radius and penetration. From sensitivity analysis, the distance between perforations represents a key source to flow convergence and restriction to flow. This work describes how model validation shows good agreement with the existing model, and demonstrates the application of the new model.

Effect of Flowrate and Pressure on the Crossflow Filtration in Textile Wastewater Treatment by Commercial UF Membrane

Textile industries are one of the greatest wastewater producers as they require a significant amount of water to be used in the dyeing and finishing processes of textile manufacturing. The number of unit operations in the technological process, the product range, the bath ratio, the mass of fiber in relation to the bath volume, and the finishing machine are some variables that will affect water consumption in the textile industry. As a result, generally, a typical textile plant may consume a volume of water between 100,000 and 300,000 m3 annually. As textiles address a substantial portion of human requirements, it is predicted that by 2050, there will be 160 million metric tonnes, three times as much clothing as there is today. Membrane technology in wastewater treatment is a recent interest arising technique and garnering the industrial application’s interest, owing to its ease of setup and low energy requirement. Crossflow membrane filtration is commonly used in the industry, attributed to its tangential flow across the membrane mechanism, leading to low fouling. This study investigated the textile wastewater’s effluents using crossflow ultrafiltration (UF) membrane filtration. The effect of the operating parameter in terms of pressure and flowrate of the crossflow system were performed to evaluate it permeate flux performance. The study’s outcome reveals pressure increases from 2 bar to 4 bar, the water flux enhances dramatically from 156.26 L/m2hr to 591.98 L/m2hr, and the water flux further increases constantly from 4 bar to 10 bar. On the other hand, the flowrate positively affects the permeate flux, where the flux was enhanced from 651.01 L/m2hr to 726.08 L/m2hr when adjusting the flow rate from 2 LPM to 6 LPM. The results from this study suggested that crossflow membrane filtration system could be commercially feasible due to its permeate flux performance.

Experimental investigation on parameter optimization of liquid spectral beam splitter for continuous photocatalytic hydrogen production accompanied with photovoltaic power generation under solar full spectrum

Effective utilization of solar energy is of great significance for a sustainable future. Herein, we report a cascade system for hydrogen-electricity co-production (PH-PV) utilizing solar full spectrum. The output performance of the system can be precisely adjusted by controlling certain parameters of liquid spectral beam splitter (LSBS) which contains TiO2 nanoparticle suspension simultaneously generating hydrogen via a photocatalytic reaction process. Typically, the thickness of LSBS, the loading amount of TiO2, the flowrate of suspension and the light intensity have been investigated in detail. It is found that LSBS is necessary in our system as it could ensure the safe operation of PV while the light intensities larger than 8 suns. With the decrease of the thickness or loading amount of photocatalyst, more electricity could be produced by PV module but less hydrogen from PH module. Further increase of above two parameters simultaneously could lead to aggregation and settlement of particle suspension in LSBS, which is detrimental to the optical absorbance of the system. Besides, changing the flowrate will diversify the surface features of particles by shear-induced effect. At optimal flowrate, the particles in LSBS could exhibit oscillation characteristics under synergistic effect of shear force and gravity, which would lead to excellent light absorption and transmittance. Furthermore, an obvious gain for both hydrogen and electricity output and system efficiency could be obtained through increasing light intensity appropriately. Finally, the improved merit function (MF) was employed to evaluate the performance of hybrid system and more obvious effect of flowrate on MF value than other parameters was found. The optimal MF value of 3.07 was reached when flowrate was 60 mL/min. Our work is expected to provide important guidance for the optimization of PH-PV cascade system driven by outdoor direct solar energy.

Enhancing Seawater Salinity through Spray-Assisted Evaporation: Investigating the Effect of Nozzle Sprayer Diameter and Feed Flowrate on Evaporation Rate using Multiple Regression Analysis

Salt production plays a vital role in life due to its essential minerals. Traditional salt production methods using direct solar rays are the most common in Indonesia. It needs a large area and several weeks extended to evaporate sea water into concentrated brine. It is very weather dependent. This study investigates the utilization of a spray-assisted evaporator to increase the salinity of seawater for salt production. The experimental setup consisted of a custom-designed spray evaporator that atomized seawater into fine droplets. A series of experiments were conducted to analyze the effect of different operational parameters, including feed flow rate (1000 ml/min; 1200 ml/min; 1400 ml/min; 1600ml/min; 1800ml/min) and diameter of nozzle sprayer (1 mm; 2 mm; 3 mm) on the average of evaporation rate. The results demonstrated that Higher spray flow rates and smaller droplet sizes positively correlated with increased evaporation rates, leading to higher salt concentrations in the collected brine. Optimizing the Impact of nozzle sprayer diameter and flow rate on the average evaporation rate utilizing multiple linear regression and deriving the Equation ,where x1 represents the seawater feed flow rate, and X2 represents the nozzle sprayer diameter.

3D computational fluid and particle dynamics simulations: metrics of aerosol capture by impaction filters * *Contribution of NIST; not subject to U.S. copyright. Certain commercial equipment, instruments, software, or materials are identified in this paper in order to specify the experimental procedure and virtual experimentation adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is

Human studies provide valuable information on components or analytes recovered from exhaled breath, but there are limitations due to inter-individual and intra-individual variation. Future development and implementation of breath tests based on aerosol analysis require a clear understanding of how human factors interact with device geometry to influence particle transport and deposition. The computational fluid and particle dynamics (CFPD) algorithm combines (i) the Eulerian approach to fluid dynamics and (ii) the Lagrangian approach to single particle transport and deposition to predict how particles are carried in fluids and deposited on surfaces. In this work, we developed a 3D multiscale CFPD model to provide insight into human factors that could be important to control or measure during sampling. We designed the model to characterize the local transport, spatial distribution, and deposition of polydisperse particles in a single impaction filter of a commercial aerosol collection device. We highlight the use of decoupling numerical strategies to simultaneously quantify the influence of filter geometry, fluid flowrate, and particle size. Our numerical models showed the remarkable effect of flowrate on aerosol dynamics. Specifically, aerosol mass deposition, spatial distribution, and deposition mechanisms inside the filter. This work as well as future studies on the effect of filter geometry and human factors on aerosol collection will guide the development, standardization, and validation of breath sampling protocols for current and emerging breath tests for forensic and clinical applications.

CFD simulation of a spiral-channel dust separator for removal of black powder from natural gas pipelines

A spiral-channel dust separator was investigated experimentally and numerically for its efficiency to separate black powder from natural gas pipelines. Effects of gas flowrates and concentration of black powder on separation efficiency and pressure drop were studied. The size distribution (0.15–5 µm) of the black powder particles was measured. Efficiency for the finest particles (mean 0.327 µm) reached 86%, compared to < 1% for a high-efficiency Stairmand cyclone of equal throughput capacity. The separation efficiency reached spiral-channel dust separator 100% for particles > 1 µm. Results of CFD simulations are reported for velocity and pressure fields in the channels, particle separation contours, and local enrichment within the channels. Calculations showed that the radial contraction and diversion of the gas flow at the separator's outlet generated highly decontaminated air above the clean air inlet tube. The distance between the separator outlet and the cleaned gas inlet has been identified as a significant design parameter due to its impact on the separation efficiency. Modeling results showed further that reducing the swirling angle of the channels leads to a decrease in pressure drop with minimal effect on separation efficiency. An evaluation of the RNG k-ε code is provided as well.

Modelling and optimization of sorption-enhanced biomass chemical looping gasification coupling with hydrogen generation system based on neural network and genetic algorithm

Chemical looping gasification of biomass (BCLG) can realize the production of pure syngas without an extra purification process. By coupling steam oxidation of oxygen carrier in BCLG, pure hydrogen can be generated meanwhile, which is a promising clean energy. An enhanced BCLG process coupling with hydrogen generation is constructed in this work, aiming to realize effective co-production of syngas and hydrogen. The coupled effects of temperature and material flows of gasifier on the gas yield, lower heating value (LHV) of syngas and gasification efficiency are numerically investigated. The effects of temperature and steam flowrate in oxidizer are changed to investigate their effects on hydrogen production. Based on the simulation results, an accurate back-propagation neural network (BPNN) is trained and tested for the performance prediction of this syngas and hydrogen co-production system. The prediction accuracy of this BPNN model is quite high with a correlation coefficient of 0.99967. Finally, the optimization of this system is conducted based on the BPNN model and genetic algorithm (GA) to make the H2/CO ratio close to 2 and maximize hydrogen production simultaneously.

Effects of impinging object on geometrical flame features of horizontal jet flames

Accidental release of hydrocarbons can result in jet fires which have the potential to escalate accidental events to catastrophes. Jet fire can impinge on nearby equipment surface or a pasive firewall to make the fire plume temperature and the radiant heat flux complex. The present work experimentally investigated the flame characteristic of free horizontal jet fires and the impingement effect using propane as fuel, with different nozzle diameter, and exit velocity. To analyse the effect of flowrate to jet flame condition, the flow rates range between 30 and 600 g/min were employed with horizontal separation distance from the main source to target was at 0.8-m and 1.2-m. The results show that, the incremenet of flame features are faster for free release than impinging release. The presence of object downstream affect the flame profiles at some point. Thus, new correlations were proposed for the prediction of projected flame length and trajcetory length.

Effects of Flowrate of Additional Shielding Gas on the Properties of Welded Seam Using Twin-Wire GMAW Welding for Duplex Stainless Steel

Aiming to diminish the defects caused by high-speed pulsed GMAW (Gas Metal Arc Welding), such as lack of penetration, lack of fusion, humping and undercut, this paper proposes an improved twin-wire GMAW welding process by introducing the impact of additional shielding gas on the molten pool, and the effects of different shielding gas flowrates on the mechanical properties and microstructure of the welded seams were investigated. The purpose of introducing additional shielding gas was to use the airflow hood formed by gas injection to isolate air. The impact force generated by the jet might change the original natural solidification mode of the molten pool, which had the effect of improving weld formation and stirring the pool. The airflow hood formed during the process of the additional shielding gas jet impact welding of the molten pool might extend the protection time for the surface of the welding molten pool. The 2205 duplex stainless steel plate was used as the base material for the butt welding test, and the welded seams were subjected to a tensile test, hardness analysis, and metallographic analysis. The results indicated that as the flowrate of additional shielding gas increased in the range of 8 L/min~16 L/min, the width of the welded seam increased and the height of reinforcement decreased gradually. However, a weld seam with a lower middle region and higher sides would appear when the gas flowrate became excessively large. Under the identical welding current and for welding speeds of 160 cm/min, 180 cm/min and 200 cm/min, respectively, the joint formed under the flowrate of 12 L/min had the highest tensile strength (824.3 MPa) among the test specimens under different flowrates of 8 L/min, 12 L/min and 16 L/min. The test results indicated that the jet impact force was relatively moderate when the flowrate of the additional shielding gas was 12 L/min, and thus was optimal for the welded seam.

Carbon capture from humid gases using alkaline-promoted polypyrrole by a vacuum swing adsorption process

Post-combustion carbon capture from humid flue gas is one of the urgent research projects for achieving the target of carbon neutrality in near future. Nitrogen-containing polymers are considered as a promising adsorbent for carbon capture in flue gases due to their potential water resistance. Here, two-step synthesis of alkaline-promoted polypyrrole (AP-PPy) with water resistance was investigated as an adsorption material for carbon capture and separation. It was found from chemical and physical analysis that the alkaline-promoted sample kept the similar morphological structure as the pristine polypyrrole but possessed more amino groups. The adsorption of single component gases revealed that the adsorption amounts of CO2, CH4, and N2 were 1.31, 0.28 and 0.065 mmol/g at 303 K respectively, among which the CO2 uptake was 80% higher compared with the original polypyrrole. The breakthrough point of AP-PPy in moisture is comparable to that of dry mixture, but the dynamic CO2 adsorption capacity is calculated to be larger than that of dry condition. A single-bed three-step vacuum swing adsorption cycling device was constructed in the laboratory and the effect of adsorption time, vacuum pressure and feed flowrate on product purity and recovery were explored with over 50 cycles in each condition to ensure cyclic steady adsorption, thereby also verifying the recyclability of AP-PPy. The excellent CO2 adsorption and separation properties demonstrated that AP-PPy can be a promising material for post combustion carbon capture.

Flowrate effects on the lateral coalescence of two growing bubbles

AbstractThe coalescence of two growing bubbles presents unique characteristics compared to static bubble coalescence. The gas injection flowrate significantly affects the different stages of bubble evolution, which is poorly understood. In this study, we investigate the flowrate effects on the lateral coalescence of two growing bubbles experimentally. The synchronous bubbling from adjacent needles is achieved using water to push air. During the bubble growth process, we find that the initial nonlinear evolution of bubble volume is because the bubble emerges as a small spherical cap with a large curvature radius and apparent contact angle. As the neck expands after bubble coalescence, the injection flowrate accelerates the neck evolution compared to the case without air injection. We find the neck expansion time decreases linearly with increasing flowrate, while the expansion speed increases with flowrate, but only in the early stage. Moreover, we propose a new theoretical expression that predicts the neck radius well at all the flowrates. At the post‐coalescence oscillation stage, the average projection area of the coalesced bubble increases linearly with time, except for periodic oscillations. Besides, we find that the injected air primarily influences the coalesced bubble's height, which in turn affects the projection area.

In-situ desorption of hydrogen sulfide from activated carbon: effect of temperature, pH and flowrate

In-situ desorption of hydrogen sulfide from activated carbon: effect of temperature, pH and flowrate

10 Validation of an Aerosol Exposure-Air Liquid Interface (AE-ALI) System to Facilitate Realistic Hazard Identification of Nano-Sized Aerosols

Abstract To facilitate hazard characterisation for inhaled engineered nanomaterials we have established an aerosol exposure air-liquid-interface (AE-ALI) system, incorporating a Cultex RFSTM cell exposure system. While offering potential benefits in terms of more realistic aerosol exposure mode over traditional submerged in vitro models and being in-line with the principles of the 3Rs, (replace, reduce and refine animal use), detailed system characterisation is required to produce reliable and reproducible results. As such, this work looked to fully characterise our AE-ALI system with a view to optimising cell viability of system controls and deposition quantity, uniformity, and reproducibility for engineered nanomaterials. Using a nano-CeO2 aerosol, the effects of exposure conditions and system parameters (e.g. temperature, electrostatic precipitator voltage and airflow) on deposition efficiency, pattern and reproducibility were investigated using ICP-MS. While results showed that appropriate choice of operating parameters can produce broadly uniform deposition, reproducibility was low, and dose monitoring during exposures is recommended. After initial optimisation of the system for deposition, the effect of exposure duration, well size and flowrate on cellular responses (e.g. cytotoxicity (LDH) and selected gene expression (IL-8, CXCL1, HMOX1, SPP1) of system controls (H2O aerosol) was investigated using human lung alveolar (A549) and primary small airway epithelial cells. Results indicate that even after optimisation for cell health, the system itself is “toxic” to cells in comparison to incubator controls, with increasing effects observed with exposure duration meaning exposure durations must be minimised. Results from this study highlight the need for detailed characterisation of AE-ALI systems prior to use.