Outlet Flow Rate Research Articles

Study on Flow and Cavitation Characteristics of an Energy Storage Chamber Type Common-Rail Injector

Abstract The high-pressure common-rail fuel injection system is one of the key technologies of diesel engines, which directly affects engine combustion. An energy storage chamber type common rail injector was studied in this paper. The injector is considered to have good control of pressure fluctuation by utilizing a special chamber inside its body. To investigate the flow and cavitation characteristics of the injector, a computational fluid dynamic model was built and validated by experimental data. The flow performance of the energy storage chamber, control valve, and SAC was conducted. The results show that the flow inside the energy storage cavity is smooth, and there is almost no cavitation phenomenon. Although the eccentric valve needle of the control valve will accelerate the flow rate, it will cause a serious cavitation phenomenon, which should be avoided. Increasing the diameter of the injector needle will weaken the cavitation, but it will cause the injector needle valve outlet flow rate to decrease. Finally, for the SAC cavity, increasing the cavity radius, increasing the nozzle inlet angle, and reducing the nozzle length can improve the discharge coefficient and optimize the flow characteristics of the injector.

A Novel Topological Optimization Method for Multi-Substance-Sensor Microfluidics Devices

Intellectual biochemical detection is an essential part of a smart society, which is important for future personal health management. The judgment process of health level should be carried out by comprehensive consideration of multiple indicators. To achieve that, multi-substance sensors are necessary. Due to the high-throughput and rapid detection characteristics, the multi-material testing microfluidic devices are promising bio-monitoring devices. To ensure the detection accuracy of the multi-substance-detection microfluidic devices, the topological structure of the channels must be designed carefully. Not only the flow rate but also the substance residue is decided by the topological structure of the channels. Thus, in this paper, we report a genetic algorithm-based topological optimization method for microfluidic devices. The material residue is modeled as the energy dissipation caused by friction. The topology and the position of the inlet and outlets are jointly optimized to minimize the energy dissipation with different desired flow rates at the outlets. The proposed genetic algorithm-based two-tier method enhanced global search ability. The simulation and experiment results show that our algorithm can decrease the energy dissipation on the premise of ensuring the outlet flow rate with comparable computational complexity.

Inversion-based model for quantitative interpretation by a dual-measurement points in managed pressure drilling

Deep wells control safety problems have always been the focus of attention due to the influence of complicated geological conditions, such as high-temperature and high-pressure (HTHP). Considering the mathematical model is only approximation of reality, thus the continuous transmission of real-time measurements is more popular, which can be used to identify the undetermined downhole parameters and improve accuracy of the model predictions. In the current study, we use two pressure while drilling tools to monitor downhole parameters in real time. Firstly, combined with the unscented-Kalman-filter (UKF) algorithm, a well hydraulics forward model with density factor and friction factor based managed-pressure-drilling (MPD) system is developed to quantitatively analyze the actual transient annular pressure. Secondly, a new multi-phase flow inversion model is established by determining the inversion parameters as gas kick rate and the position of the gas kick, which is used to track the values of pressure and outlet flow rate in real-time. The results of the case indicate that the inversion accuracy of the inversion parameters increases with the distance between dual-measurement points, and the reasonable value is selected as 30 m. Additionally, the proposed model is successfully validated using synthetic data and experimental data, where the maximum errors in predicting the position of the gas kick are only 3.1% and 5.3% when tuning the model stably tends towards the true value, respectively. The proposed model achieves accurate quantitative interpretation and analysis of downhole gas kick conditions, further clarifies the previously unknown key parameters of downhole gas kick, and has important significance for the realization of safe and efficient drilling.

Performance investigation and evaluation of a new three-piston pump energy recovery device for small scale desalination system

Energy recovery device is a crucial part for decreasing the energy consumption of membrane desalination system. To meet the energy conservation requirements in small scale desalination system, a new three-piston pump energy recovery device integrating the high pressure pump and booster pump is investigated and evaluated. The flow characteristics in pressure exchanging cylinders are investigated through the numerical method. The operating performance is experimentally evaluated in a membrane desalination system at the seawater pressure and flowrate of 5.00 MPa and 6.10 m3/h. The numerical results indicate that the continuous flow and pressure transition can be realized through the cooperation of three hydraulic pistons in operation. Both the inlet and outlet flowrates demonstrate the half-sine variation trends. The maximum deviation between simulation and experiment is 2.70%. The experimental results prove that the device can achieve the stable pressure exchanging, and the pressure and flowrate fluctuation amplitudes are 0.60 MPa and 0.60 m3/h. The energy recovery efficiency is as high as 82.03% which contributes to a specific energy consumption of 3.62 kW·h/m3 in desalination. This paper provides a new type of multi-functional energy recovery device for the membrane desalination system.

Suppression of flow pulsations and energy consumption of a drug delivery roller pump based on a novel tube design

A drug infusion peristaltic pump is experimentally studied, examining its performance for three flexible tubes, two cylindrical, and an innovative one of lenticular cross-section with an inflated part. Using water as flowing medium, the pump outlet flow rates were measured at nine phases of the semi-period, based on phase-locked 2D-PIV data. The roller disengagement phase showed to cause a reduction of the outlet flow rate, and in a lesser degree, the engagement phase. Flow acceleration at the pump outlet occurred when only one roller was squeezing the tube. The gauge pressure waveforms at the pump inlet and outlet although noisy had a phase lead with respect to the flow rate. According to the pump motor current waveform, the work of the forces necessary for the tube deformation was about 10 times higher than that of the fluid viscous and inertial forces. Among the three examined flexible tubes, the pump performance was the best when the lenticular tube was used, presenting the highest volumetric efficiency and the smallest outlet flow rate pulsations, pressure amplitudes, and energy consumption. The high pump performance is attributed to the innovative inflated part of the lenticular tube, its cross-sectional shape and its higher compliance compared to the other tubes.

Research on Seepage Characteristics of Y-Shaped Fractures under Different Fracture Roughness

Fractures are widely distributed in coal, and studying the seepage characteristics of fluids in fractures is of great significance for unconventional natural gas extraction and prevention of gas disasters. In this work, based on the W-M fractal function, a Y-shaped fracture model with different roughness is established. The seepage characteristics of Y-shaped fracture with different roughness are interpreted from two perspectives. Firstly, the seepage law of the Y-shaped fracture with the same roughness is studied. Secondly, the fluid competitive diversion capacity caused by the difference of branch fracture roughness is discussed. The results show that the fracture roughness is an important factor affecting the seepage characteristics of the fracture. When the roughness of the fracture is identical, the outlet flow rate, velocity, and Re are all positively correlated with pressure, and the flow regime is unchanged. The increase in the fracture roughness will lead to a significant flow rate and momentum loss, resulting in maximum loss up to 45.44%, besides, enhance the flow resistance of the fracture, Re increasing by 771, 713, 489, and 355, respectively, at four patterns. And there is a threshold DM between 1.1 and 1.2 so that the major influencing factor on hydraulic conductivity changes. In addition, the roughness difference between the branch fractures of the Y-shaped fracture is the key factor to control the fluid competitive diversion capacity. The larger the roughness difference, the greater difference in flow velocity, and the more significant change in flow rate proportion, which proportion differs by 4%, 44%, and 54%, respectively, and the stronger smooth branch fracture competitive diversion capacity, and the lower the rough branch fracture hydraulic conductivity. As the inlet pressure increases, the two branch fractures Re gradually increases but Eu decreases, which Eu in smooth branch fracture is smaller is 15, 19, 20, and 21 smaller than that of rough branch, respectively, and the rough branch fracture competitive diversion capacity is weakened. Both roughness difference and inlet pressure will affect the competitive diversion capacity of the Y-shaped fracture. These results are expected to provide new insights for the exploitation of underground fluid resources.

Dynamic modeling and predictive control of boil-off gas generation during LNG loading

During liquefied natural gas (LNG) loading, excessive boil-off gas (BOG) is generated due to the temperature difference between the LNG and a tank at room temperature. While one way to deal with this challenge is to gradually reduce the tank temperature via an LNG, this cool-down process may also produce excessive BOG, if not properly handled, leading to a sudden pressure change inside the tank. To this end, a model predictive control (MPC) system was formulated in this work to simultaneously regulate the pressure and temperature of the tank by manipulating the vapor outlet flow rate and the amount of LNG spray injected during the cool-down process. Specifically, a high-fidelity model of cool-down process was developed and simplified to a reduced-order model (ROM). Then, the ROM was incorporated into the developed MPC scheme which successfully computed an input profile to drive the pressure and tank temperature to target values.

Simulation and Optimization of the Ethane Cracking Furnace Using ASPEN PLUS and MATLAB: A Case Study from Petrochemical Complexes

ABSTRACT Ethylene production is one of the most abundant activities in petrochemical industries. So, the main objective is to develop detailed models to describe a pyrolysis section in the real ethylene plant furnace located at the petrochemical complex (PC1), Basra, Iraq. Those models were utilized to evaluate the effects of the reaction temperature, steam to ethane ratio (DS/HC), and feedstock flowrate on the ethylene yield using different feedstock compositions. The simulation validity was tested by comparing the simulation results with the real data collected from the PC1 and showed an acceptable similarity and reliability depending on relative error values. A genetic algorithm coded by MATLAB and Aspen Plus optimizer was used to obtain the optimal operating conditions to give a maximum profit. The optimization results of Aspen Plus and GA showed an increase in the profit equal to 10.541 and 9.823% respectively when the reaction temperature, DS/HC and outlet flowrate of hydrocarbons were in the range of 850–920°C, 0.2–0.5, and 2421–1064 Kmole/hr respectively. Also, Increasing the ethane content in feedstock leads to an increase in the feedstock production of 16–19% ethane content.

Effect of outlet impeller diameter on performance prediction of centrifugal pump under single-phase and cavitation flow conditions

Abstract In this current study, the transient numerical calculations using CFD code are carried out under different outlet impeller diameters for the flow field within a centrifugal pump under single-phase and cavitation conditions. Both qualitative and quantitative analyses are carried out on all of these results in order to better understand the flow structure within a centrifugal pump. Also, the investigations using different outlet impeller diameters configurations relating to the static pressure, velocity magnitude, vapour volume fraction variations, as well as pressure fluctuations in both time and frequency domain at the impeller and volute of the pump are analysed. Velocity and static pressure variations of the pump under different outlet impeller diameters range (200, 210 and 220 mm) are investigated. Reliable model is developed and validated, at various pump operating conditions, to analyse the characteristics of pressure fluctuations in both time and frequency domain. Cavitation occurrence, under different outlet impeller diameters and flow rates, are detected and correlated, using a CFD model (volume fraction distributions). Based on the developed model’s findings, at the set operating conditions ranges, the distribution and impact (cavitation and head-wises) of both the pressure and velocity are analysed. The average pressure fluctuation in the volute for do = 210 mm is higher than for do = 200 mm by about 6.74%, also the maximum pressure fluctuation for do = 220 mm is higher than for do = 210 mm by around 7.4%. Furthermore, the maximum pressure fluctuation in the impeller for do = 210 mm is higher than for do = 200 mm by 12.48%, also for do = 220 mm is higher than for do = 210 mm by 10.8%. The developed CFD models are proved valuable tools in identifying and optimizing the pump performance and characterization. The head for when do = 220 mm is higher than for when do = 200 mm under both single-phase and cavitation conditions by around 14.13% and 14.69%. The maximum pressure fluctuation for do = 200 mm is lower than for do = 210 mm by 41.58%. Furthermore, the maximum pressure fluctuation at the impeller for do = 220 mm is higher than the two models. There is a small clearance between the impeller and the volute for this model, leading to the pressure fluctuation amplitudes being higher than the other above models.

Dynamics of submerged jet flow in a pipe in a longitudinal magnetic field

A submerged jet flow of an electrically conductive liquid in a longitudinal uniform magnetic field is considered. The flow is formed by a sudden expansion of the flow from a hole into a pipe (with a diameter ratio of 1 to 5) filled with the same liquid at a constant flow rate. The study was carried out using the method of direct numerical simulation. The simulation results are compared with the averaged longitudinal velocity measurements obtained in the experiments on mercury. The Reynolds numbers correspond to the turbulent flow in the jet at the inlet and the laminar flow at the outlet of the pipe. In a moderate magnetic field, with an increase in the Hartmann number in the flow, turbulent transport is suppressed. The flow is largely laminarized up to the jet front, where, due to instability, it passes to turbulence. The effective length of the jet increases with increasing the Hartmann number, since the resulting electromagnetic force prevents the jet expansion. In strong magnetic fields, there is a tendency for the flow to be unstable due to the interaction of the formed secondary flows with the magnetic field. The radial components of the induced electric current arising in this case in the flow cause transverse stretching and compression of the jet profile by the electromagnetic force. Time-variable deformations of the jet profile and their spatial inhomogeneity in a magnetic field lead to the appearance of an ordered flow swirl. The swirl rate depends on the Hartmann number and, in the studied range of Reynolds numbers, does not exceed 12% of the average outlet flow rate. The development of instability is accompanied by time alternations of intervals in which the flow has significantly different amplitudes of velocity fluctuations.

Numerical study of asymmetric breakup behavior of bubbles in Y-shaped branching microchannels

Microfluidic technology based on microchannel two-phase flow has been widely used. The precise control of the bubble or droplet size in the channel plays a crucial role in designing the microfluidic systems. In this work, the bubble breakup behavior in Y-shaped microchannel is reconstructed based on the volume of fluid method (VOF), and the effects of bubble dimensionless size (1.2–2.7), outlet flow ratio (1–4) and main channel Reynolds number (100–600) on the bubble breakup behavior are systematically investigated. The bubble asymmetric breakup process is found to be divided into three stages: extension stage, squeeze stage, and rapid pinch-off stage. In the case of small initial bubble size or relatively high outlet flow rate, the bubble does not break, but only experiences the extension stage and the squeezing stage. Four flow patterns of bubble breakup are further revealed for the bubbles with different sizes and outlet flow ratios: tunnel-tunnel breakup, obstruction-obstruction breakup, tunnel-obstruction breakup, and non-breakup. With the increase of outlet flow ratio, the breakup process of the bubble gradually becomes asymmetrical, and the flow pattern shifts along the tunnel-tunnel breakup and the obstruction-obstruction breakup, gradually turns toward the tunnel-obstruction breakup and non-breakup. On this basis, the critical flow ratio of bubble breakup and the variation of daughter bubble volume ratio with outlet flow ratio are obtained for different Reynolds numbers and initial bubble sizes, and the corresponding criterion correlation equation is refined, which can provide theoretical guidance for accurately regulating the daughter bubble size after breakup.

3D-Stacked Multistage Inertial Microfluidic Chip for High-Throughput Enrichment of Circulating Tumor Cells.

Whether for cancer diagnosis or single-cell analysis, it remains a major challenge to isolate the target sample cells from a large background cell for high-efficiency downstream detection and analysis in an integrated chip. Therefore, in this paper, we propose a 3D-stacked multistage inertial microfluidic sorting chip for high-throughput enrichment of circulating tumor cells (CTCs) and convenient downstream analysis. In this chip, the first stage is a spiral channel with a trapezoidal cross-section, which has better separation performance than a spiral channel with a rectangular cross-section. The second and third stages adopt symmetrical square serpentine channels with different rectangular cross-section widths for further separation and enrichment of sample cells reducing the outlet flow rate for easier downstream detection and analysis. The multistage channel can separate 5 μm and 15 μm particles with a separation efficiency of 92.37% and purity of 98.10% at a high inlet flow rate of 1.3 mL/min. Meanwhile, it can separate tumor cells (SW480, A549, and Caki-1) from massive red blood cells (RBCs) with a separation efficiency of >80%, separation purity of >90%, and a concentration fold of ~20. The proposed work is aimed at providing a high-throughput sample processing system that can be easily integrated with flowing sample detection methods for rapid CTC analysis.

Modeling of wellbore multiphase flow with free gas influx during horizontal drilling in marine hydrate reservoirs

The wellbore multiphase flow and managed annulus pressure are key issues during drilling in hydrate reservoirs. In this study, the intercoupling interactions of free gas, drilling fluid, cuttings, and hydrates are considered, and a gas–liquid–solid multiphase four-component flow model that incorporates the hydrate phase transition is proposed. The hydrate formation and multiphase flow submodels in the unified model were verified by comparing with the collected data from a hydrate formation experiment in a flow loop and a full-scale gas kick experiment, respectively. The multiphase flow behaviors and gas kick migration, as well as the effects of hydrate phase transition, were thoroughly analyzed. Simulation results show that the hydrate decomposition in the cuttings is sufficient to cause a pit gain of 1.96 m3, which is approximately equal to that of a 3 MPa bottomhole underbalanced pressure. Thus, failure to consider this factor in multiphase flow simulation will result in significant errors in the bottomhole and formation pressure inversion. The phase transition of hydrates delay the pit gain in reaching 1 m3 by 32 min. The prediction errors of the pit gain and outlet flow rate at the initial stage of overflow can reach up to 94.33% and 6.17%, respectively, when the hydrate phase transition is neglected. Using managed pressure drilling and increasing the wellhead pressure to 1.5 MPa in the case study can ensure that the gas void fraction in the annulus is within a controllable range. This unified model can provide insights into gas kick migration and wellbore pressure control for horizontal well drilling in hydrate reservoirs.

Optimization of the Outlet Flow Ratio of Mini-Hydrocyclone Separators Using the Full Factorial Design Method to Determine the Separation Efficiency

Cyclone separators are widely used to eliminate particles flowing through pipelines in equipment from various industrial processes. Unlike general filters, cyclone separators can constantly and effectively eliminate foreign substances present in the fluid flowing through the equipment. In this study, we fabricated mini-hydrocyclone separators using the 3D printing method for application in the steam and water analysis system (SWAS) in a thermal power plant instead of the conventional strainer filter. The gravimetric method was used to measure the separation efficiency of the hydrocyclone separators and compare the weights of the sludge discharged from the underflow and overflow outlets. The outlet flow ratio was optimized by adjusting the diameters of the spigot and vortex finder of the separators, which influenced the outlet flow rate. To apply the gravimetric method more objectively, the optimum values of the diameters of the vortex finder and spigot with an outlet flow ratio of 1 were determined using full factorial design (FFD) in the design of experiments (DOE). The obtained values were verified through numerical analysis using the ANSYS Fluent software. Furthermore, after fabrication of the mini-hydrocyclone separators using an SLA-type 3D printer, we conducted a numerical analysis, and the results were compared with that of the actual experiment. It was observed that the use of FFD can effectively optimize the desired outlet flow ratio in the mini-hydrocyclone separator. In addition, the changes in the outlet flow ratio do not affect the separation efficiency of the cyclone separators.

Numerical simulation of the transient turbulent natural convection in an inclined rectangular shaped solar air heater

Due to high energy demand and adverse effect of global warming, improving the performance of solar thermal systems is of great importance. In this respect, the transient flow and thermal behavior of turbulent naturally ventilated airflow in a flat plate solar air heater (SAH) are investigated numerically. To achieve this aim, conservation of mass, momentum, and energy equations are solved for the turbulent airflow concurrently with the conduction equation inside the solid element using finite element method (FEM). The low Reynolds turbulence model is applied in the calculation of turbulent stress and heat flux, and the Boussinesq approximation is applied for computing buoyancy forces associated with the density gradient. The surface radiation is also considered explicitly in the calculations to obtain more accurate and reliable results. It is found that although based on the considered location the maximum incident radiation occurs at the optimum angle of 30°, the maximum flow rate reach to its peak when the inclination angle is 60°, in which the total increase of incident radiation is nearly 17%. It is also found that the rate of heat transfer is a decreasing function of the inclination angle (30⩽θ⩽90), such that the overall rate of heat transfer reduction is around 50%. Further, investigation of the impacts of solar radiation and air duct width on thermal performance showed that by increasing both parameter the rate of heat transfer and air flow increase by about 35% and 100% respectively. The exclusive analysis of the effects of sudden climate change on the SAH’s behavior revealed that a short time climate change leads to zero incident radiation, and considerable fluctuations in outlet temperature and flow rate.

Unsteady model for wellbore pressure transmission of carbon dioxide fracturing considering limited-flow outlet

The outlet flow rate is limited during CO2 fracturing, which significantly affects the CO2 property distribution and pressure transmission in the wellbore. In this paper, a transient wellbore flow model with a limited-flow outlet is developed to simulate the pressurization process of CO2 injection, which incorporates the compressible fluid flow governing equations, CO2 compressibility, and wellbore heat transfer. The calculation results show a good accordance with field data. The results show that the wellbore pressure and pressurization rate increase gradually with CO2 injecting under a constant inlet pump rate, and the variations in CO2 crucial properties are dominated by borehole pressurization with time increasing. Regarding the two injection patterns, a larger pressurization rate can be obtained under a lower inlet pump rate for tubing injection, while the friction pressure loss can be effectively reduced for commingled injection. Moreover, the pressurization rate increases with inlet pump rate, but also the frictional ratio and its growth rate, hence, the inlet pump rate should not be excessive. Furthermore, the inlet pressure must exceed a lower limit to prevent CO2 from gasifying, which is 4.52 MPa under the calculation condition. The model can provide more insights for the design, control, and optimization of CO2 fracturing.

Differences in Formation Mechanism of Static Pressure Circumferential Distribution of Centrifugal Compressor Under Different Operating Conditions

Abstract The casing-wall static pressure of the centrifugal compressor behaves the double-peak distribution in the circumference at small flow rates (SM) but the single-peak distribution at large flow rates (LM). A previous study shows that the double-peak distribution is induced by the redistribution of impeller outlet flow rates. In this paper, by using the similar simplified method of directly imposing pressure boundary to the diffuser outlet, the original reason for the formation process difference of pressure distribution in the circumference at different operating conditions is further investigated. The results show that at LM, under the combined action of the specific downstream pressure distribution and the flow performance of the compressor itself, alternating low/high velocity airflow zones similar to those at SM cannot be established in the diffuser when the impeller outlet flow rates are redistributed. Therefore, the static pressure can only express the single-peak distribution in the circumference. In fact, whether the static pressure exhibits the double-peak or single-peak distribution in the circumference depends on whether the impeller outlet flow mutation can destroy the original flow balance. When the flow mutation is dominant, the double-peak distribution is created, whereas when the original flow balance is prevailing, the single-peak distribution is formed.

Effect of Subject-Specific, Spatially Reduced, and Idealized Boundary Conditions on the Predicted Hemodynamic Environment in the Murine Aorta.

Mouse models of atherosclerosis have become effective resources to study atherogenesis, including the relationship between hemodynamics and lesion development. Computational methods aid the prediction of the in vivo hemodynamic environment in the mouse vasculature, but careful selection of inflow and outflow boundary conditions (BCs) is warranted to promote model accuracy. Herein, we investigated the impact of animal-specific versus reduced/idealized flow boundary conditions on predicted blood flow patterns in the mouse thoracic aorta. Blood velocities were measured in the aortic root, arch branch vessel, and descending aorta in ApoE-/- miceusing phase-contrast MRI. Computational geometries were derived from micro-CT imaging and combinations of high-fidelity or reduced/idealized MR-derived BCs were applied to predict the bulk flow field and hemodynamic metrics (e.g., wall shear stress, WSS; cross-flow index, CFI). Results demonstrate that pressure-free outlet BCs significantly overestimate outlet flow rates as compared to measured values. When compared to models that incorporate 3-component inlet velocity data [[Formula: see text]] and time-varying outlet mass flow splits [[Formula: see text]] (i.e., high-fidelity model), neglecting in-plane inlet velocity components (i.e., [Formula: see text])) leads to errors inWSS and CFI values ranging from 10 to 30% across the model domain whereas the application of a steady outlet mass flow splits results in negligible differences in these hemodynamics metrics. This investigation highlights that 3-component inlet velocity data and at least steady mass flow splits are required for accurate predictions of flow patterns in the mouse thoracic aorta.

Experimental Investigation on Performance Parameters Affecting the Efficiency of Water Type PV/Thermal Collectors with Modified Absorber Configurations

In this study, efficiency of water-type photovoltaic/thermal (PV/T) modules that convert solar energy into both electrical and thermal energy were investigated. By using identical photovoltaic (PV) cells, one PV module and five PV/T modules differed in thermal structure with different diameters, amount and layout of absorber tubes, and type of absorber sheets were fabricated with lamination technique. Firstly, the electrical efficiency of all samples under Standard Test Conditions was tested by a sun simulator. Efficiency values were between 12.56% and 12.68% under STC. Furthermore, outdoor tests were carried out to investigate the effect of temperature on PV modules in ambient conditions using PV/T samples. In order to determine the efficiency of the units, parameters such as solar irradiation, voltage and current values, inlet and outlet water temperature and flow rate of PV/T modules and ambient temperature were measured. It was observed that the electrical performance of PV/T modules was higher than that of the PV module due to the cooling effect of water circulation over the cells. PV/T module with the highest thermal efficiency was also determined. Total efficiency value of PV/T modules in outdoor conditions were attained between 60.68% and 67.14%.

3D Printed Microfluidic Spiral Separation Device for Continuous, Pulsation-Free and Controllable CHO Cell Retention.

The development of continuous bioprocesses—which require cell retention systems in order to enable longer cultivation durations—is a primary focus in the field of modern process development. The flow environment of microfluidic systems enables the granular manipulation of particles (to allow for greater focusing in specific channel regions), which in turn facilitates the development of small continuous cell separation systems. However, previously published systems did not allow for separation control. Additionally, the focusing effect of these systems requires constant, pulsation-free flow for optimal operation, which cannot be achieved using ordinary peristaltic pumps. As described in this paper, a 3D printed cell separation spiral for CHO-K1 (Chinese hamster ovary) cells was developed and evaluated optically and with cell experiments. It demonstrated a high separation efficiency of over 95% at up to 20 × 106 cells mL−1. Control over inlet and outlet flow rates allowed the operator to adjust the separation efficiency of the device while in use—thereby enabling fine control over cell concentration in the attached bioreactors. In addition, miniaturized 3D printed buffer devices were developed that can be easily attached directly to the separation unit for usage with peristaltic pumps while simultaneously almost eradicating pump pulsations. These custom pulsation dampeners were closely integrated with the separator spiral lowering the overall dead volume of the system. The entire device can be flexibly connected directly to bioreactors, allowing continuous, pulsation-free cell retention and process operation.