Volumetric Air Flow Rate Research Articles

A method for bubble volume measurement under constant flow conditions in gas–liquid two-phase flow

Measuring the volume of a bubble, especially at its detachment, is a basic subject in gas-liquid two-phase flow research. A new indirect method for this measurement under constant flow conditions is presented. An electronic device is designed and constructed based on laser beam intensity. This device calculates the frequency of the bubble formation by measuring the total time of the formation process and counting the number of bubbles crossing the laser beam. The bubble volume at detachment can be calculated by dividing the volumetric flow rate of air by the frequency of bubble formation. The latter and the bubble volume at detachment are measured for three different heights of water above the the tip of the orifice (50, 100, and 150 mm), three orifice diameters (1, 2, and 3 mm), and different gas flow rates between 2000 and 10000 ml/hr. Comparing and validating the results with the results of the image processing (IP) method and the correlations presented by other studies shows the strong accuracy of the present method.

Foam fractionation for effective recovery of resveratrol from the leaching liquor of Polygonum cuspidatum by using partially ethylated β-cyclodextrin as collector and frother

In this work, foam fractionation has been proposed to recover resveratrol from the leaching liquor of Polygonum cuspidatum. Resveratrol is a natural polyphenol without surface activity. For achieving the adsorption of resveratrol on the gas-liquid interface, a biological surfactant of partially ethylated β-cyclodextrin (partially Eβ-CD) was prepared. First, the inclusion behavior between partially Eβ-CD and resveratrol was investigated. Resveratrol molecular could easily enter into the cavity of partially Eβ-CD from its wide rim due to the possible driving forces of charge transfer and dipole-dipole interactions. The experiments of foam properties suggested that partially Eβ-CD could decrease the surface tension of aqueous solution, thus generating stable foam. By using partially Eβ-CD as collector and frother, foam fractionation was performed. Under the suitable conditions of partially Eβ-CD concentration 0.680 g/L, loading liquid volume 250 mL, volumetric air flow rate 40 mL/min, pore diameter of gas distributor 0.45 mm and pH 4.0, the enrichment ratio and the recovery percentage of resveratrol reached 2.79 and 73.84%, respectively. The concentration of resveratrol in the foamate was as high as 0.050 g/L. This work is expected to provide a new strategy to effectively recover a non-surface-active material from its aqueous solution, and to facilitate the industrialization of foam fractionation.

Milling Characteristics and Nutritional Quality of Paddy Rice Processed Using Biomass Powered Stove

Milling and nutritional quality of rice processed using wood and rice-husk briquette powered biomass stove was investigated. There was significant difference (p≤0.05) in milling attributes of the processed rice among volumetric air flow rates. There was no significant difference (p≥0.05) in the milling attributes of the processed rice between the treatments. The L-values ranged from 60.20 to 62.40 with the least values at 0.18 m³/s and 0.20 m³/s and the highest value at 0.25 m³/s. The percentage head rice (HR) ranged from 98.50 to 98.83% which were fairly the same. The lowest and highest values of (HR) were obtained at 0.25 m³/s and natural air flow. Milling recovery (MR) ranged from 68.21 to 68.60% with the highest values at 0.25 m3/s and the least value at natural air flow. Similar trends were observed for milling attributes with exception of chalkiness that remained constant for all treatments. The values for other quality parameters of the milled rice showed that fire wood and briquette recorded fairly similar values, although, briquette recorded higher values in some cases with the exception of chalkiness that showed exactly the same trend at different treatments. The carbohydrate content of the rice processed using briquette was higher than those processed using fire wood and most of the other quality indices such as protein, ash which is an indication of presence of mineral elements were higher for briquettes compared with fire wood. The results revealed that powering the stove was advantageous since the quality indices of the rice were enhanced.

Performance of a Retrofitted Multicyclone for PM2.5 Emission Control

This paper presents on the performance of a retrofitted multicyclone system, which aims to increase the collection efficiency of PM2.5 (i.e. particulate size fraction ≤ 2.5 μm) emission. The multicyclone was retrofitted by extracting 15% and 20% of the total volumetric air flow rate at the dust hopper of the unit using an additional Induced Draft Fan. The total collection efficiency with and without the extraction was measured at various air volumetric flow rates and particulate mass inlet concentration. The results showed that there was a reduction of 12% to 54% depending on the inlet concentration of PM2.5 emission in the stack with compared to without extraction increasing the collection efficiency of the retrofitted multicyclone. The finding suggests that a simple technique of applying gas extraction at the dust hopper of a multicyclone as reported in this study able to increase the overall performance in fine particulate collection.

Accuracy analysis of air torque position dampers based on blade profiles and damper locations

The primary concern of this paper is a single-blade air torque position damper used for the indirect measurement of volumetric air-flow rates by measuring the moment of airstream force exerted on the blade and the damper position. The purpose of the paper is to analyze the accuracy of the air velocity measurements and the adequacy of the damper mathematical model on the basis of the blade profile and the damper location in a duct system. The analysis was performed on the basis of the experimentally obtained results. Four different blade profiles (flat, V-groove, symmetrical airfoil, and non-symmetrical airfoil blades) were taken into account, as well as three different damper locations in the duct system (at the duct entrance, within the duct, and at the duct exit). Two blade orientations at the duct entrance were examined relative to the direction of air-flow (with front and rear mounting flanges). It was determined that the blade profile and particularly the damper location in the duct system affect the measurement accuracy and the adequacy of the damper mathematical model provided the blade angle of attack is less than or equal to 30?, i. e. within the range of a more open damper.

RANCANGAN DAN PEMBUATAN ALAT SIMULASI SISTEM VENTILASI TAMBANG PADA LABORATORIUM UNTUK PEMBELAJARAN VENTILASI TAMBANG

Underground mine activities is not detached by mechanical ventilation system for supplying air demand for worker’s breathing, dirty air and toxic gases removing, dust reducing, and heat and humidity controlling. There for makes safer and enjoyable in working. To facility the study of mine ventilation in campus, the simulation study about mechanical underground mine ventilation system was applied. To do this research, the describtion about mechanical ventilation system of underground mine is necersary and also we need pay attention with the parameters in air qualities and quantities controlling witch are not over limit to the limit value (NAB). Describing how to control the air qualities and quantities, the writer got sample as well as PT. AICJ. PT.AICJ’s ventilation system is forcing system with some parameter like air velocity, wet and dry temperature, relative humidity, tunnel dimension, and around of gases concentration in air at mine front. Gases measured to wards the concentration of O2, CO2, CH4, and H2S. In this research, the writer designed and created a simulation of ventilation system, with autoCAD 2014 modeling advises. In the other hand the material that, used for equipment is iron plate 1 mm thickness. Volumetric air flow rate produced by forcing fan (18” diameter size) is 0.23m 3 /second with 26 0 C effectively temperature. Medium air flow rate is 0.24m/second with is 25,3 0 C effectively temperature. High air flow rate is 0,26m/second with 24,7 0 C effectively temperature, while volumetric air flow rate of forcing fan 16” diameter size is o,26 m 3 /second with 24,4 0 C effectively temperature, for exhaust fan (4”size) produced 0,18 m 3 /second volumetric air flow rate with 26,5 0 C effectively temperature . so the simulation equipment ventilation can show measure result by quantity and quality airflow characteristic. Keywords : Ventilation Simulation Equipment, Air Quality, Air Quantity, Ventilation Pressure

Techno – economic analysis of ventilation driven through solar metallic wall for a hostel building of National Institute of Technology Raipur India

The aim of present work is to investigate theoretically the ventilation flow rate produced using solar metallic wall system. In this effort, the effect of various design parameters on the performance of solar metallic wall system is evaluated under the climatic condition of Raipur (21.2514° N, 81.6296° E), Chhattisgarh. A computer simulation program based on the mathematical model of proposed system has been developed using MATLAB software. The performance of solar metallic wall system is evaluated by predicting the volumetric air flow rate. The effect of air gap, height and different metallic sheets are determined. It has been observed that with increase in air gap and height, volumetric air flow rate increases, about 203 % increase in volumetric air flow rate is observed for increase in air gap from 0.1 m to 0.5 m and 57 % increase in volumetric air flow rate is observed for increase in height from 1 m to 2 m. The best performance of solar metallic wall system is observed on using aluminium as metallic sheet as compared to the other chosen materials. The ratio of volumetric air flow rate obtained for iron, copper, and aluminium is 1, 1.11, 1.45 that shows, volumetric air flow rate for ventilation by metallic wall of aluminium is about 45% more than its competitor. Finally the system is proposed for a hostel of NIT Raipur and it is concluded that 3024 kWh per year of energy is saved if solar metallic wall is used in place of conventional electrical system. The amount of carbon-dioxide emitted to atmosphere is also reduced by 0.02 tonne per year. The payback period of total solar metallic wall units required in place of exhaust fans to completely ventilate the hostel building during day hours is coming out to be 7 years and 8 months.

A novel membrane-assisted fermentation coupling with foam separation for improving the titer of polymyxin E

ABSTRACTIn this paper, a novel membrane-assisted fermentation coupling with foam separation (M-FCFS) technology was developed to separate polymyxin E from its broth immediately. The effects of starting aeration time, membrane, volumetric airflow rate in foam column, and nitrogen source (i.e. peptone, also known as foam stabilizer) on the production of polymyxin E were studied. Under the optimal conditions, the total titer (TT) of polymyxin E reached 1.29 × 106 IU, resulting in a 50.4% improvement compared with the uncoupling experiment (8.60 × 105 IU). This work combined the advantages of foam separation and membrane filtration, and provided a promising technology for the production of polymyxin E.

Performance evaluation of a v-groove solar air collector for drying maize (Zea mays) in lraq

In this work, a solar drying system was constructed, consisting of three parts (solar collector, drying chamber, and air blower). Solar collector having V-corrugated absorption plate of two air passes, a single glass cover was used. The total area of the collectors is 2.04 m². The dimension of the drying chamber is 1.06, 0.66 and 0.56 m for width, depth, and height, respectively. 38 kg of corn were dried. The moisture content was reduced from 21 to 13% within four hours drying. The drying air temperatures at the inlet of the dryer were found in the range of 30 to 45°C when the range of ambient air temperature was from 8.5 to 20°C and total solar radiation intensity was from 270 to 560 W/m2. Increasing volumetric air flow rate from 0.025 to 0.030 m3/s raises the daily solar collector efficiency by 3.25%, while increasing volumetric air flow rate from 0.030 to 0.035 m3/s raises the solar daily collector efficiency by 11.11%. The drying rate is reduced with the decrease of moisture content. Efficiency of the collector is very much dependant on air flow rate. Key words: Solar energy, solar air collector, two passes collector, V-corrugated collector, solar drying, performance evaluation.

Development of a dual optical fiber probe for the hydrodynamic investigation of a horizontal annular drive gas/liquid ejector

A dual-channel optical fiber probe was developed to quantify the bubble characteristics (void fraction, velocity, and bubble size) in a gas–liquid annular ejector system. Water is pumped upstream of the ejector contraction. Since a low pressure region exists downstream in the ejector diffuser, this permits air to be sucked into the flowing liquid by jet pump action and the inlet air volumetric flow rate is measured by a flow meter. Verification of the void fraction (range 0.15–0.5) measured by the optical fiber probe was then possible and deviations were generally around ± 5%. Also, bubble velocity was measured using the optical probe by cross-correlating signals from the two fibers whose tips are separated by a known distance. Alternatively measuring bubble velocity using a particle image velocimetry method provided validation for the optical fiber probe system where a high speed camera was used to capture instantaneous bubble images at time intervals of 0.125ms. Excellent agreement between the velocities using both methods is reported. For bubble size measurements, analyzing the temporal signals from a single probe enabled estimation of the size of a bubble. Bubble sizes measured ranged between 1.5 and 6.0mm and size distributions were constructed for different ejector water volumetric flow rates ranging from 0.0022 to 0.0063m3/s. LabVIEW provided a convenient platform for coding the algorithms for estimating the void fraction, bubble velocity and bubble size. For further comparison, a CFD study of the ejector system was done, and the vertical radial profiles of the void fraction were compared with those obtained by the optical fiber system and these showed good agreement.

Particle deposition on flat sheet membranes under bubbly and slug flow aeration in coagulation-microfiltration process: Effects of particle characteristic and shear stress

Empirical and numerical techniques were used to study particle deposition on flat sheet microfiltration (MF) membranes during surface water treatment under single-phase flow (no aeration) and two phase flow (aeration with bubbly or slug flow) in the presence and absence of metal coagulants and polymers. Pre-coagulation of the particles reduced the hydraulic resistance of the cake layer by 87.5% compared with non-coagulated particles (2.0×1012m−1 vs 0.25×1012m−1) for the same solids load. Moreover, pre-coagulated particles were more susceptible to the effects of aeration and were more readily dispersed from the filter cake on the membrane. Computational fluid dynamic simulations of shear stress on the membrane surface over a viscosity range of 1.10×10−3 to 1.38×10−3Pas, indicated that the peak shear stress induced by slug flow (15Pa) was far larger than that by bubbly flow (1.4Pa) at the same volumetric air flow rate, however, the shear stress under bubbly flow was more evenly distributed over the membrane surface. The cake resistance was higher under slug flow (0.05×1012m−1) compared to bubbly flow condition (0.025×1012m−1). Moreover, cake redispersion was found to be greater under bubbly flow compared to slug flow. The implication is that bubbly flow is preferable to slug flow for removing deposited aggregates that control flux during the coagulation-microfiltration of surface water using flat sheet membranes.

Energy and cost savings potential of oscillating heat pipes for waste heat recovery ventilation

Abstract The feasibility of using finned oscillating heat pipes (OHPs) for heat exchange between counter-flowing air streams in HVAC air systems (i.e., outdoor and exhaust air flows), along with the associated cost savings in typical North American climates, is investigated. For a prescribed temperature difference and volumetric flow rate of air, rudimentary design parameters for a viable OHP Heat Recovery Ventilator (OHP-HRV) were determined using the e -NTU (effectiveness-Number of Transfer Unit) method. The two-phase heat transfer within the OHP-HRV is modeled via effective evaporation/condensation heat transfer coefficients, while the latent heat transfer required to initiate OHP operation via boiling and evaporation is also considered. Results suggest that an OHP-HRV can possess a reasonable pressure drop ( 5 kW. The proposed OHP-HRV can possess an effectiveness near 0.5 and can pre-cool/heat HVAC air by >5°C. Potential energy and cost savings associated with using an OHP-HRV were estimated for commercial building envelopes in various regions of the United States. It is found that the proposed OHP-HRV can save more than $2500 annually in cities that have continental climatic conditions, such as Chicago and Denver, and for the selected locations the average yearly cost savings per building is found to be on-the-order of $700. Overall, the OHP-HRV shows potential in effectively reducing energy consumption and the operational cost of air handling units in buildings.

Kinetics of Extraction of Tributyl phosphate (TBP) from Aqueous Feed in Single Stage Air-sparged Mixing Unit

Abstract The mass transfer studies involving kinetics of extraction of Tributyl phosphate (TBP) saturated in 0.3 M nitric acid using different organic extractants viz. normal paraffinic hydrocarbon (NPH), kerosene, dodecane etc. have been performed in a novel air-sparged single stage mixing unit. Based on the mechanism, a simple kinetic model (analogous to first order) is proposed and experimental data was analyzed. The optimization studies including the effect of diluent, % TBP in NPH, Organic to Aqueous phase (O/A), air flowrate and the nitric acid concentration in aqueous phase have been performed. The experimental and modeled kinetic results suggest that the optimized conditions for the extraction of TBP (174 ppm to 65.5 ppm) from aqueous 0.3 M HNO3 feed are found to be, 3 % TBP in NPH as extracting solvent, O/A is 1/1 and volumetric air flowrate is 15 LPM. However, if pure NPH used as an extractant with these operating conditions 100 % removal can be obtained.

Modified β -CD-Cu ion complex and yam mucilage assisted batch foam fractionation for separating puerarin from Ge-gen ( Radix puerariae )

Abstract At present, the large scale application of batch foam fractionation is still in confrontation with many problems and difficulties, especially for the enrichment of non-surface-active materials. It is difficult to select a suitable surfactant as the collector when a non-surface-active material can only form a stable association with the expensive surfactants or has not any interactions with the commercially available surfactants. The objective of this work was to investigate the feasibility of batch foam fractionation for recovering such a non-surface-active material, puerarin. Yam mucilage, an abundant byproduct from the manufacture of yam starch, was used to generate a stable foam phase based on its good foamability. According to the properties of puerarin and yam mucilage, β -cyclodextrin ( β -CD) was selected as a basic material to establish an association between them. The results of fluorescence sensitization experiments indicated that puerarin could form an equimolar inclusion complex with β -CD and the inclusion constant was 405.8. Subsequently, β -CD was modified by introducing carbon disulfide and copper (Cu) ion. Then, puerarin could be adsorbed on the gas-liquid interface in the form of ternary complex with modified β -CD-Cu ion complex and glycoprotein molecules (see Fig. 7). Batch foam fractionation was carried out by using the crude extracting solution as the initial feeding solution, in which the concentration of puerarin was as high as 4.6 g/L. Under the suitable conditions of temperature 50 °C, pH 6.0, loading volume of feed solution 400 mL, the pore diameter of gas distributor 0.450 mm, additive volume of yam mucilage 30 mL and volumetric air flow rate 100 mL/min, the enrichment ratio and the percent recovery of puerarin were 4.3 and 82.3%, respectively. This strategy could be generalized to the separation of various non-surface-active materials due to the low cost and the diversiform cavity dimension of cyclodextrins.

Systematic process optimisation of fluid bed coating

A design of experiments approach was used to investigate the impact of bed temperature, volumetric air flow rate, spray rate and concentration of the coating solution on fluidised bed coating of particles. The process was analysed in terms of agglomeration tendency, efficiency and coating quality. Response surfaces were fitted to the experimental data from which optimal factor combinations were calculated in order to improve the coating quality. The coating quality was assessed by a previously developed method based on a dissolution test to efficiently measure the thickness, the uniformity and the completeness of the coating. It was demonstrated that the method provides a reliable way to assess the various measures for coating quality.

β-cyclodextrin assisted two-stage foam fractionation of bromelain from the crude extract of pineapple peels

For reducing the costs of separating bromelain from its crude extract, a two-stage foam fractionation technology with β-cyclodextrin as an activity protector was developed using the foam fractionation column with vertical sieve trays (VSTs). By studying the effects of VSTs, volumetric air flowrate, β-cyclodextrin concentration, aeration time and temperature, the two-stage foam fractionation technology were optimized. The results show that VSTs effectively improved the activity recovery by enhancing the adsorption of bromelain at the gas-liquid interface while β-cyclodextrin significantly reduced the activity loss induced by the gas-liquid interface. At β-cyclodextrin concentration 0.60mg/mL, a high specific activity of 165.6U/mg, 7.4 folds of that in the crude extract, was obtained with an activity recovery of 45.2% by using the optimized two-stage foam fractionation technology. Compared to those without β-cyclodextrin, activity recovery and specific activity obtained satisfactory relative increases of 34.1% and 110.7%, respectively.

3D computational fluid dynamics study of a drying process in a can making industry

In the drying process of a can making industry, the drying efficiency of a thermal drying oven can be improved by adjusting the volumetric air flow rate of the blower. To maximize drying efficiency, an optimal flow rate is needed. Consequently, a three-dimensional computational fluid dynamics (CFD) is used to provide simulation according to the response of air velocity, air temperature and evaporated solvent concentration with respect to changes in volumetric air flow rate in the drying oven. An experimental study has been carried out to determine the evaporation rate of the solvent. To validate the models, the process data obtained from the CFD is compared with that obtained from actual data. In the accurate models, the simulation results demonstrate that the decrease in volumetric air flow rate provides no major discrepancy of the air velocity patterns in all dimensions and decreases the maximum temperature in the oven. Consequently, this decrease in volumetric air flow rate rapidly increases the evaporated solvent concentration in the beginning and then gradually decreases over the length of the oven. In addition, further reduction of the flow rate gives lower heat loss of the oven up to 83.67%.

Drying kinetics of cotton based yarn bobbins in a pressurized hot-air convective dryer

In this study, the drying kinetics of cotton bobbin drying process in a pressurized hot-air convective bobbin dryer was investigated, and a drying model was introduced for the simulation of drying. Tests were conducted for drying temperatures of 70℃, 80℃, and 90℃; effective drying air pressures of 1, 2, and 3 bars; three volumetric flow rates of 42.5, 55, and 67.5 m3/h; and for three different bobbin diameters of 10, 14, and 18 cm. Optimum drying conditions were specified in terms of drying time and energy consumption. Results indicate that the total drying time depends significantly on the drying temperature, pressure, and volumetric flow rate. Results show that the minimum energy consumption is obtained for low values of drying air temperatures and pressures, and for moderate and high values of drying air volumetric flow rates. It was also found that the Page model is suitable for simulating the drying behavior of cotton yarn bobbins. Finally, results show that effective diffusion coefficient values are between 1.132 × 10−7 m2/s and 3.453×10−7 m2/s depending on the values of drying parameters.

Recovery of yam mucilage from the yam starch processing wastewater by using a novel foam fractionation column

Abstract It is difficult to separate a surface-active material from a wastewater with a high viscosity by foam fractionation. In order to solve the problem, a novel foam fractionation column with vertical sieve tray (VST) placed in the foam phase was developed for effectively recovering yam mucilage from the viscous yam starch processing wastewater. The effects of design parameters of VST on its foam drainage properties were investigated. The results showed that the suitable design parameters of VST were the number of trays in VST 5, the number of vertical sieve caps in each tray 4 and the number of sieve pores in each cap 28. Meanwhile, the suitable operating conditions were also determined. Under the conditions of pH 6.0, temperature 25 °C, volumetric air flow rate 50 mL/min and loading liquid volume 500 mL, the enrichment ratio and recovery percentage of yam mucilage were 5.70 and 91.21%, respectively, which were 3.77 and 1.55 times higher than those in the control column. The above results indicated that the novel foam fractionation column with VST in the foam phase could simultaneously improve the enrichment ratio and the recovery percentage of yam mucilage by strengthening foam drainage. This work was aimed at developing a novel foam fractionation column for effectively recovering a valuable byproduct from a viscous food processing wastewater and further facilitating the industrial application of foam fractionation in food industry.

Effective improvement of defoaming efficiency using foam breaker with synthetic sponge cylinders in foam fractionation

For effectively improving the physical defoaming efficiency in foam fractionation, a new foam breaker with synthetic sponge cylinders was developed and its defoaming mechanism was analyzed. Due to synthetic sponge’s high water absorption ability, it resulted in a large pressure difference inside and outside the liquid film to rapidly collapse the foam. The defoaming efficiency was studied on the basis of the effects of the type and number of synthetic sponge cylinders, SDS concentration, volumetric liquid fraction and volumetric air flowrate. The results show that the synthetic sponge cylinder with 0.23±0.05mm in mean pore diameter and 70.0±0.5% in mean porosity had the highest defaoming efficiency and a larger number of synthetic sponge cylinders resulted in a higher defoaming percentage. Under suitable conditions, defoaming percentage of the new foam breaker with 4 of the optimal synthetic sponge cylinders reached 100.0%. Furthermore, the synthetic sponge cylinders had much higher defoaming efficiency, lower equipment cost, lower energy consumption and simpler preparation than perforated plates and paddle agitator. So the foam breaker with synthetic sponge cylinders is highly promising in industrial defoaming.