Constant Air Flow Rate Research Articles

Combustion reactivity of sewage sludge hydrochar derived from hydrothermal carbonization via thermogravimetric analysis

Wastewater treatment plant sludge contains a high concentration of organic compounds that can be used to produce fuel viahydrothermal carbonization (HTC). This study investigated the combustion reactivity and kinetic parameters of hydrochars produced to understand the combustion behavior of the solid fuel derived from HTC. The hydrochar was produced at various temperatures ranging from 150 to 300 °C, reaction times ranging from 30 to 150 min, and solid loadings ranging from 10% to 30%. The combustion behavior of sewage sludge (SS) and hydrochar was evaluated using thermogravimetric analysis with a constant air flow rate (100 mL/min) and heating rate (10 °C/min) from ambient temperature to 900 °C. It was observed that the HTC temperature, reaction time, and solid loading influenced the combustion characteristics and kinetics of the hydrochar. Additionally, the hydrochar exhibited higher ignition and burnout temperatures and a lower peak temperature than SS, indicating superior performance and reactivity in combustion. The combustion kinetic analysis also revealed that the hydrochar had a range of lower activation energy (29.12–41.60 kJ/mol) than SS (52.95 kJ/mol). Therefore, hydrochar derived from SS has the potential to be used as a substrate for solid fuel production for future renewable energy sources.

Investigation into the Operating Performance of a Novel Direct Expansion-Based Air Conditioning System

This study introduces a novel direct expansion air conditioning (DX AC) system with three evaporators (DX-TE) to enhance indoor temperature and humidity control. Operating in two modes, the DX-TE system provides variable cooling output, adapting to fluctuating indoor cooling loads while maintaining uniform air supply. Experimental and simulation studies were conducted to investigate the system’s operational characteristics. An experimental setup was established to obtain preliminary steady-state data, followed by the development and validation of a steady-state mathematical model. Simulation studies were then performed to optimize the evaporator sizes. The results indicate that the DX-TE system delivers variable cooling capacities at a constant compressor speed and airflow rate, outperforming conventional variable frequency DX AC systems in cooling and dehumidification. The evaporator area ratio significantly impacts the system’s performance, with smaller ratios yielding a larger output range. As the area ratio increases from 1:1 to 1:3, the cooling capacity range in Modes 1 and 2 increases by 33.6% and 14.3%, respectively, while the dehumidification range expands by 58.6% and 51.69%.

Aerosol dosimetry in the whole conducting zone of a murine left-lung using CF-PD and LSFM images

Aerosol dosimetry in respiratory airways is relevant for pulmonary drug delivery and inhalation toxicology. Consequently, computational fluid-particle dynamics (CF-PD) modelling of pulmonary aerosol delivery is an active research field. Additionally, mice are the most commonly used animals in medical research. Technological advances have provided information on whole mice lung morphologies with unprecedented high resolution. Therefore, in this study, we used high-resolution light sheet fluorescent microscopy (LSFM) images of a healthy C57BL/6 mouse lung with a constant air flow rate of 72 ml/min, to extract an anatomical 3-dimensional (3D) geometry of the entire airway tree of the left lung from the primary bronchi to the most distal bronchioles excluding the trachea. The airways were segmented based on an order- and generation-based method. Also, to compare the morphological data and regional deposition, a generation-based investigation including 25 generations was employed in the present model. One-way coupling of CF-PD modeling was applied to model an intubated and mechanically-ventilated mouse. Maximum values of the velocity and vorticity magnitude of 3.2 m/s and 200,000 1/s were reached in the second order, respectively, and maximum pressure and wall shear stress levels were 30 Pa and 3.5 Pa, respectively. Finally, order- and generation-based particle deposition efficiency and dose per lung area were obtained for the particle size range of 1 μm ≤ dp ≤ 10 μm yielding pronounced hotspot deposition patterns mainly near the proximal bifurcations. The results showed a positive correlation between deposition efficiency and particle size due to a size-dependent increase in inertial and gravitational effects. Maximum regional deposition and normalized dose was seen for 10 μm particles in the 1st order of the murine left lung. Smaller peak sizes of deposition efficiency were seen in the third and fourth orders of the mouse left lung due to almost complete loss of the largest particles in lower order airways. It also justifies the close to zero deposition efficiency in the highest orders (fifth to sixth). Both lung morphology as well as total and regional aerosol deposition showed reasonably good agreement with empirical data from the literature. The present CF-PD model with accurate realistic lung morphology, improves our knowledge of airway aerosol deposition hotspots. The obtained modeling method and the qualitative results can be implemented on human airways.

The augmentation of the heat recovery by using evaporative cooling in HVAC applications: Experimental study

An experimental study was conducted to investigate the impact of evaporative cooling on heat recovery within HVAC systems. This study involved the development of a specialized test rig comprising two air passages connected by a wickless heat pipe heat exchanger (wickless HPHE). Additionally, an evaporative cooling pad was integrated into the cold air return duct. The evaporative cooling process effectively lowered the temperature of the cold air, which was subsequently directed through the wickless HPHE condenser. This occurred at a variable mass flow rate ratio, in contrast to the constant mass flow rate of warm air passing through the wickless HPHE evaporator section. The study encompassed a range of mass flowrate ratios, specifically 1, 1.5, and 2. The thermosiphon heat pipe was charged with acetone at a 60 % filling ratio. The results clearly demonstrated that evaporative cooling played a pivotal role in enhancing the heat exchanger's performance. Notably, the temperature differential observed in the wickless HPHE evaporator surpassed that in the HPHE condenser, primarily due to the influence of evaporative cooling. The highest temperature difference recorded in the HPHE evaporator was 17.8 °C, indicative of the most substantial heat recovery achieved. Importantly, the effect of evaporative cooling significantly improved the performance of the wickless HPHE by more than 48 %.

Numerical analysis of single SC-50-800 and SC-50-500x2-x4 group centrifugal cyclones: efficiency comparison

Centrifugal cyclones are important devices used to separate solids or liquids from gas streams using centrifugal forces. They are widely used in various industrial processes and air and gas purification systems. In this work, numerical modeling and study of the efficiency of cyclones of various configurations are carried out: single cyclone SC-50-800, group cyclones SC-50-500x2 and SC-50-400x4. To conduct the study, the engineering software package Comsol Multiphysics 6.1 was used with the addition of the Flow Simulation module, specialized for modeling hydrodynamic processes. To simulate turbulent flows, the v2-f model was chosen, which is often used in the case of swirling flows. The computational experiment was carried out at a constant air flow rate of 4500 m3/h. Based on the obtained numerical data, an analysis of the effectiveness of various cyclone configurations was carried out. The results of the study show that the operating efficiency of group cyclones significantly exceeds the efficiency of single cyclones. This is confirmed by analysis of separation parameters and comparison of performance indicators of various cyclone configurations. The data obtained can be useful for the design and optimization of gas stream purification systems in various industrial and environmental applications.

Experimental Investigation of Solar Air Heater with Energy Storage Unit

The present study investigates a single-pass solar air collector (SAC) linked to a thermal energy storage unit. This system is designed to store energy by using a cement mortar molds storage bed during daylight hours and subsequently reutilize it at night. A solar collector was used in this research, which was consecutively connected to the cement mortar molds bed. High-density cement mortar molds (570 kg) were used as a storage medium. The experiments were conducted on clear days for two random days at a constant airflow rate (0.0217 kg/s) for the climate of Mosul City, Iraq. The study assessed the parameters influencing the thermal performance of the SAC integrated with the cement mortar molds storage bed. Measurements of solar radiation intensity and air temperatures at various locations were recorded. The data indicated that the cement mortar molds storage bed achieved a temperature difference of approximately 10? post-sunset, with this difference sustained for 4-5 hours. The cement mortar molds bed demonstrated the capability to retain heat for an extended post-sunset, releasing it during nighttime.

Role of Air Staging in a Batch-Type Fixed Bed Biomass Combustor under Constant Primary Air

Staged combustion of biomass is the most suitable thermo-chemical conversion for achieving lower gaseous emissions and higher fuel conversion rates. In a staged fixed bed combustion of biomass, combustion air is supplied in two stages. In the first stage, primary air is provided below the fuel, whereas in the later stage, secondary air is supplied in the freeboard region. The available literature on the effects of air staging (secondary air location) at a constant primary air flow rate on combustion characteristics in a batch-type fixed bed combustor is limited and hence warrants further investigations. This study resolves the effect of air staging, by varying the location of secondary air in the freeboard at five secondary to total air ratios in a batch-type fixed bed combustor. Results are reported for the effects of these controlled parameters on fuel conversion rate, overall gaseous emissions (CO2, CO and NOx) and temperature distributions. The fuel used throughout was densified hardwood pellets.Results show that a primary freeboard length (distance between fuel bed top and secondary air injection) of 200 mm has higher fuel conversion rates and temperatures as well as lower CO emissions, at a secondary to total air ratio of 0.75 as compared to primary freeboard length of 300 mm. However, NOx emissions were found to be lower for a primary freeboard length of 300 mm as compared to 200 mm. An increase in secondary to total air ratio from 0.33 to 0.75 resulted in higher freeboard temperatures and lower CO as well as NOx emissions. The outcomes of this study will be helpful in the effective design of commercial scale biomass combustors for more efficient and environmentally friendly combustion.

Optimizing the parameters of the air disc atomizer for the low volume desalination spraying of cotton crops

The article presents the results of a multi-factorial experiment to justify the parameters of a rotating sprayer. Optimization of the parameters of the pneumatic disk atomizer shows that with the correct choice of the specific liquid flow rate (qi), disk radius (r) and the number of radial channels (η r) at a constant air flow rate, it leads to obtaining the required median-mass droplet diameter. Therefore, when justifying the diameter of sprayed drops, it is necessary to consider a combination of the specific flow rate of the liquid and the radius of the disk. To obtain a monodisperse spray of drops with a median-mass diameter d= 80…120 µm, the disc radius should be in the aisles r=75.8…83.4 mm, the specific liquid flow rate qi= 0.61…0.96 l/min and the number of radial channels for pairs of disks in the aisles η p = 4.59… 5.75 things.

Thermal performance of a hybrid solar dryer through experimental and CFD investigation

AbstractSolar drying comes under clean energy technology that aims to dry food products hygienically. The present work discusses the development of an energy‐efficient and cost‐effective hybrid‐type solar dryer for drying 15 kg of food products. Experiments and CFD modeling of the solar drying system have been carried out for drying tomato slices. The maximum efficiency of the collector has been obtained as 74.1% and 66.96%, respectively with and without using exhaust hot air recirculation. Performance indicators such as convective heat transfer coefficient, overall loss coefficient, drying efficiency, and collector efficiency factor have been obtained as 7.743685 W/m2°C, 5.94189 W/m2°C, 32.89%, and 0.987%, respectively. The coefficient of determination (R2) is calculated as 0.9863, 0.9919, and 0.9755 for the first, second, and third day, respectively, representing a higher order of fit of getting a performance evaluation of the collector. A p‐value is obtained as 0.49375 (>0.05) from a paired sample t‐test signifying no statistical significance difference between the predicted and actual experimental results of collector efficiency. For a constant mass flow rate of air, the maximum temperature inside the drying chamber and wall radiative heat flux obtained from experiments and CFD simulation are in good agreement, thus satisfying the validation. Further, the dryer can be used during the night time by using an electric coil producing a satisfactory drying effect. It is lightweight and easily portable to capture maximum solar radiation.Practical applicationsThe present solar dryer is most suitable for drying applications in food processing industries due to the clean and hygienic process of drying. It is easily portable to any location to capture maximum solar radiation. It is lightweight and has low construction, and maintenance costs. It is the most efficient and fast drying compared to open sun drying and can be used for large‐scale drying in industrial applications. The present study is about CFD simulations of the solar dryers for drying 5 kg of tomato slices. The drying efficiency has been increased by utilizing exhaust hot air circulation. Both the simulation and experimental results have been validated and further dryer has been used during night time by using an auxiliary heating element.

Thermogravimetric assessment for combustion characteristic of torrefied pellet biomass from agricultural solid waste

This present paper is focused on the investigation of combustion characteristics of torrefied pellet biomass from agricultural waste. Four biomass pellet samples such as sugarcane bagasse, Napier grass, Palm Empty Fruit Bunches, and Cassava stem were torrefied in a designed cylinder tubular pyrolysis reactor. The reactor was set up under 30 min of residence time, and the temperature reaction was varied at 200, 250, and 300 °C in an inert atmosphere. The torrefied products were then characterized in terms of their psychochemical properties such as proximate, ultimate, calorific value, and combustion properties. The combustion properties of raw and torrefied biomass pellets during the combustion process were investigated by the thermogravimetric analyzer Exstar SII TG/DTA7300. The samples were heated at an ambient temperature up to 800 °C at a constant heating rate of airflow at 10 °C/min in airflow. The results showed that the moisture content and volatile matter of torrefied pellets decreased by 2 to 5% and 8 to 14%, subsequently. Otherwise, the fixed carbon content is up to three times higher than the raw material. The study conclusively that torrefaction can also able to enhance combustion performance in terms of ignition and burnout temperature, ignition and burnout index, and combustion rate. The results shows that, the ignition and burnout temperatures of torrefied pellets are higher than raw material. The ignition and combustion index of torrefied pellets are lower than raw material, and the torrefied pellets have a longer burning time and a higher combustion temperature.

Experimental study for comparison of thermal comfort and air age between two combined ventilation systems with chilled ceiling considering occupant density

AbstractDue to the global spread of diseases and epidemics, the need to maintain a clean indoor atmosphere has received increasing attention in recent years. Therefore, there will be a need to clearly estimate and define the areas that affect human exposure to pollutants, taking into account the occupied density, which is the primary importance of this research. The capacity of the chilled ceiling combined with mixing ventilation and personal ventilation systems has been studied and compared to the chilled ceiling with mixing ventilation in terms of mean air age, temperature distribution, CO2 concentration, and thermal efficiency, with the best flow rate of the proposed system considering the occupied density in a thermally insulated office room experimentally in the climate of Iraq (Hilla, a hot and dry climate). Twelve tests were performed for four different cooling loads with cooled ceilings (0%, 0.25%, 50%, and 80%), at a constant supply air flow rate with two PV airflow modifiers for three cases. As the cooling load treated by a chilled ceiling increased, the average air temperature increased with height in all cases. The lowest values of average air age appeared in the occupied area in the case of a chilled ceiling with mixing ventilation. This study shows that the chilled ceiling combined with a mixing ventilation and personal ventilation system with a flow rate of 7.5 L/s provides thermal comfort and higher air quality in the occupied area. based on the values of air exchange efficiency and occupants’ air exchange efficiency. As a result, a flow rate of 7.5 L/s is the best option for protecting occupants from direct pollution in the breathing zone and in the surrounding microclimate, because the lower the ventilation rate, the less air is changed for occupants.

Experimental studies of frequency of rotation of smooth rotating disk with coaxial-lateral air flow

The article presents methods for determining the main parameters of a rotating atomizer sprayer. The choice of research methodology is justified based on the general pattern of liquid atomization by rotating atomizers, taking into account the influence of the air flow on them. The main indicators affecting the sprayed drops' dispersal are the air flow rate and the rotational speed of the pneumatic disk atomizer. Therefore, the correct choice of the method for determining the rotational speed ω of a pneumatic disk atomizer makes it possible, at a constant air flow rate, to obtain the required median-mass diameter of the atomized droplets. To obtain a high-quality air-droplet flow, there must be a combination between the initial speed of the main drops discharged from the spray disk's periphery and the fan installation's air flow speed.

EFFECT OF FLANGE VIBRATION ON AIRFLOW PASSING THROUGH A DIFFUSER WITH KNOWN GEOMETRY

A diffuser-augmented wind turbine is used to enhance the overall performance characteristic of the wind turbine. Flanges near the trailing end of the diffuser create a pressure difference that accelerates the free-stream velocity into the diffuser, increasing the performance of the wind turbine. In the present analysis, a numerical method is used to analyze the effect of flange vibration at different amplitude and operating frequencies. The diffuser is operated at no-load (<i>C</i><sub>t</sub> = 0) condition for all cases. An optimum opening angle is determined in the absence of flange vibration at a constant airflow rate and is used for further analysis. Performance characteristics such as diffuser speed-up ratio and coefficient of power are estimated for all cases. It is found that the velocity at the centerline oscillates with the same frequency as that of the flange.

Investigation of Air Solar Collector with Energy Storage for Domestic Purposes

ABSTRACT
 In the current study, a three-pass solar air collector (SAC) connected with a stone storage bed is investigated. The thermal energy storage was used to store energy during the day time and then re-use it at night or during the cloudy hours. Four solar air collectors were used in this research which were connected consecutively to the stone storage bed. High density black stones (440 kg) of different sizes and weights were used as a storing medium. The physical properties of the stones were measured in the lab. The experiments were conducted on clear and partly cloudy days for three random days at a constant air flow rate (0.0377 kg/s) for the climate of the Dohuk city, Iraq. The parameters that affect the thermal performance of (SAC) were evaluated with integration of the stone storage bed. The solar radiation intensity, air temperatures at different locations were measured. Obtained data showed that the stone storage bed gives a temperature difference of about 10℃ after sunset and lasts for about 4-5 hours. The used stone bed has the property of acquiring stored heat for a long time after sunset which was released at night or on partly cloudy days.

Preliminary Study Of Nitrate Production By Plasma Discharge As Potential Fertilizer Material

Nitrogen-based fertilizer production mainly involves the Haber-Bosch process, which synthesizes Ammonia via a chemical reaction of N2 from the air and H2 under high temperature and pressure conditions in the presence of a catalyst. However, the environmental concern for greenhouse gas emissions and high energy consumption triggers other Nitrogen fixation method development. The non-thermal plasma oxidation of N2 into Nitrate is a promising method since it has lower energy consumption and a more suitable process condition with a better environmental profile. This study tested the designed plasma discharge reactor tube to produce nitrate from air N2 with varying voltage, time, and airflow rate operating conditions. Nitrate concentration was analyzed using a UV-Vis spectrophotometer. The results show that nitrate concentration changes linearly with the applied voltage in a constant airflow rate and length of treatment time. The highest performance of the plasma discharge reactor was achieved on a 6 kV applied voltage with a flow rate of 0.2 L/min and a treatment time of 40 minutes where the obtained nitrate concentration was 7.7 ppm, which indicated the potential plasma discharged nitrate production for green fertilizer application. Further study shall be carried out to enhance the performance.

MMA: The Fight Against Sleep Apnea

IntroductionAffecting approximately one billion people worldwide, obstructive sleep apnea (OSA) occurs when an individual’s airway self‐obstructs during sleep. Persons suffering OSA are generally less healthy and are more likely to develop a myriad of conditions known collectively as Metabolic Syndrome. One OSA solution is maxillomandibular advancement surgery (MMA), involving maxillomandibular complex (MMC) repositioning. While the surgery reports an 87‐100% success rate, the mechanisms of how MMA reduces OSA is not as clear. Further, a proportion of patients are dissatisfied with their appearance after the procedure. This project aims to simulate ventilation in cadavers who have undergone MMA surgery using an incremental MMA approach to measure airway resistances and relate these changes to resulting facial alteration.SurgeryThe MMA procedures were performed by the same dental surgeon. The oral distraction devices (KLS Martin, Florida) were left intact for the entirety of the experiment for manual jaw advancements. For each dependent variable, the MMC was advanced from 0mm to 14mm in 2mm increments.VentilationA patient ventilator (LTV 1000 Pulmonetics, Minnesota) simulated ventilation at each MMA increment. Tidal volumes (TV) were calculated for each cadaver at 6ml/kg of body mass, over the same breathing frequency (12 breaths/minute), resulting in constant air flow rates. At each advancement of the MMC, airway resistance (R) is calculated using breath‐by‐breath analysis of peak inspiratory pressure and plateau pressure at each flow rate. A minimum of 10 breaths were used to calculate R at each MMA increment.Facial ScansAfter every ventilation condition, topographical scans measured 3D changes in the face (Space Spider Scanner, Artec, California). Scan areas of interest extended from hyoid to infraorbital foramen and to the tragi, laterally. The 3D meshes enable calculation of discreet skin surface alterations at each MMA increment and comparisons to baseline topography. Comparing incremental changes to baselines as percentages, a facial alteration index (∆F%) allows comparisons across individuals.DiscussionDetermination of cadaveric breath‐by‐breath airway forces during MMA is novel and ongoing. Preliminary results (n=1, F, 27yrs, 46kg) demonstrate inverse relationships between incremental MMA and R. With each 2mm MMA, R decreased an average of 4.3 cmH2O/L/s (r = ‐0.82). The foundation of the change in R is supported by an average decrease in peak inspiratory pressure of 3.67 cmH2O (r = ‐0.95) and an average decrease in plateau pressure of 2.81 cmH2O (r = ‐0.97) with each 2mm MMA. Use of ∆F% analysis enables demonstration of the relationship between MMA, airway resistance, and resultant facial alteration. The combined approaches are hypothesized to predict relationships between airway resistance and facial alteration at each level of MMA. Determination of this relationship will be a powerful tool, enabling surgeon and patient to be involved in informed decision‐making.

The impact of oxygen content in the primary air supply on fuel burning rate and pollutant emissions in a forced-draft biomass stove

Forced-draft biomass stoves have been proposed as a substitute for traditional solid fuel stoves in rural areas. The change in the O2 content of the supply air via flue gas recirculation (FGR) significantly affects the combustion and pollutant emission performances of this household stove type, which has not been thoroughly investigated. In this study, O2 content control system was designed to accurately adjust the O2 content of the primary air supply for a typical household forced-draft biomass stove. Then, six conditions with an O2 content of 16%, 17%, 18%, 19%, 20%, and 21% were tested. The dynamic burning rate and emission rates of carbon monoxide (CO), nitrous oxides (NOx), and particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5) were measured for each O2 content. The results showed that the average burning rate of the six O2 contents ranged from 9.6 to 16.9 g/min. There was a positive linear relationship between the average burning rate and the O2 content in the primary air supply. The CO and PM2.5 emission amounts exhibited the concave and convex quadratic relationships with O2 content, respectively, while trends in NOx emission amount had a negative linear relationship with the O2 content. The real-time burning rate and pollutant emission rates exhibited different trends that influenced the amount of emissions. When FGR was utilized with a constant primary airflow rate, an O2 content of 19.7% may be optimal for household biomass stoves. This study provides basic information on air supply design of household biomass stoves, which is essential for future clean stove design and improvement.

Experimental Investigation on the Cooling Performance of a Counterflow Dew Point Evaporative Cooler

In this study, an innovative indirect evaporative cooler is presented and experimentally analysed. A prototype was assembled for the experimental investigation of the system and tested in the laboratory environment under the conditions of constant air flow rate of 350 m3/h, circulating water temperatures of 15°C and 20°C, inlet air temperatures of 25°C and 30°C and lastly inlet air humidity of 9g/kg and 13g/kg, respectively. Based on the data obtained during the experiments, calculations were performed for the cooling capacity, cooling efficiency, energy efficiency and exergy efficiency of the system for each case. The findings showed that the highest wet bulb efficiency, dew point efficiency and EER of evaporative cooler were found to be 0.91, 0.62, and 0.77, respectively.

Experimental study on the synthetic dust loading characteristics of air filters

• The loading characteristics of bag-type air filters for ASHRAE and A2 fine test dust were studied through experiments. • A pressure drop empirical equation model was proposed via linear regression. • The dust loading mass is introduced in the evaluation of the air filter pressure drop. The energy consumption of filtration is an important part of the energy consumption of HVAC systems, so reasonable evaluation of the average pressure drop during the entire life cycle of an air filter is very important. However, the loading characteristics of bag-type air filters for ASHRAE test dust and A2 fine test dust have not been well studied. Medium-efficiency bag-type air filters widely used in HVAC systems were selected as the research object, and dust loading experiments at different concentrations of ASHRAE test dust and A2 fine test dust were conducted in order to reveal the evolution of air filter pressure drop under different air flow rate and dust loading state conditions. Based on experimental data and via linear regression, an empirical equation model of pressure drop calculation with air flow rate and dust loading mass as independent variables is proposed, which can be used to predict the pressure drop of air filters. The results show that the absolute value of relative error between the pressure drop values predicted by the empirical equation model and experimental results is basically within 7%, and that the model is accurate and reliable. The applicability of the model is verified through the experimental data from references. Based on this model, it is possible to predict the pressure drop of air filters in HVAC systems under constant or variable air flow rates and different dust loading masses, and to reasonably evaluate the average pressure drop throughout the life cycle of the filter.

Investigations on the effect of rotational speed on the transport of air-water two-phase flows by centrifugal pumps

This study presents experimental and numerical investigations on air-water flows in a centrifugal pump, extending our previous studies. The main objective of the present article is to examine the influence of rotational speed on pump performance. For that purpose, the pump performance was considered and extensively compared for two different rotational speeds, i.e., 650 rpm and 1000 rpm, covering different single and two-phase flow conditions. To allow flow visualization, the impeller and the pump body were manufactured from transparent materials, and a high-speed camera was employed for recording the two-phase flow regimes. The performance of the pump was illustrated and reported for either a constant gas volume fraction or a constant air flow rate at the pump inlet. The desired operating conditions at the inlet were achieved using various predetermined experimental procedures to study the performance hysteresis. Pump surging and breakdown conditions were also considered. Additionally, 3D URANS single-phase numerical simulations were performed to explain additional internal flow details. The moving-mesh approach combined with the k-ω SST turbulence model has been used for that purpose. The simulations agree well with the experiments in most cases. Overall, the results show that increasing the rpm enhances two-phase mixing, which leads to various and significant improvements regarding two-phase pumping performance.