In this study, we assessed the performance characteristics of five different magnetorheological micropump designs, two of which were our proposed designs, while others were from the existing designs in the literature. Comparisons have been performed based on physics-based simulations, and the fully coupled magneto-solid-fluid interaction simulations were carried out in COMSOL Multiphysics software. For a fair and meaningful comparison, both the material and geometric properties were kept the same, and the simulations were run for one complete pumping cycle. The results showed that the proposed flap and duckbill valve models could pump 1.09 µL and 1.16 µL respectively in 1 s, which was more than the rest of the existing micropump models. Moreover, at 0.5 s, when the magnetic flux density was maximum, the flap and duckbill valve models could pump almost twice as fluid as some of the existing valve models did. The results also demonstrated that the flap and duckbill valve models were nearly five times faster than some of existing models. In conclusion, the proposed two micropump models could propel more net fluid volume than the existing micropump designs, experienced low leakage during the contraction and expansion phase, and had faster response times. We believe that the present study provides valuable insights for future micropump designs, which have an extensive range of application areas, ranging from insulin dosing systems for T1D patients to artificial organs to transport blood and from organ-on-chip applications to micro-cooling systems.

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In this study, we propose a duckbill valve microfluidic pump that relies on an electromagnetic actuation mechanism. An FEA/CFD-based approach was adopted for the design of the device due to the coupled electromagnetic–solid–fluid interactions in the device. The simulation methodology was confirmed with the previously published data in the literature to ensure the accuracy of the simulations. The proposed optimum duckbill valve micropump can pump 2.45 µL of fluid during the first 1 s, including both contraction and expansion phases, almost 16.67% more than the basic model. In addition, the model can pump a maximum volume of 0.26 µL of fluid at the end of the contraction phase (at 0.5 s) when the magnetic flux density is at maximum (0.027 T). The use of a duckbill valve in the model also reduces the backflow by almost 7.5 times more than the model without any valve. The proposed device could potentially be used in a broad range of applications, such as an insulin dosing system for Type 1 diabetic patients, artificial organs to transport blood, organ-on-chip applications, and so on.

In this paper, we studied a flap valve micro-fluidic pump that relies on an electromagnetic actuation mechanism. The upper wall pump chamber is made of a smart material called magnetorheological elastomer (MRE). Under a magnetic field, the upper wall contracts, and the amount of contraction depends on the intensity of the applied magnetic field, which can be controlled via electromagnets. Moreover, flap valves mounted inside this micropump can convey fluids unidirectionally. A Finite Element Analysis (FEA)/Computational Fluid Dynamics (CFD)-based approach was embraced for the design of the device due to the coupled electromagnetic-fluid-structural interactions in the device. Simulations were carried out in COMSOL Multiphysics software. The performance characteristics of the pump were presented and discussed. In addition, a parametric study was conducted to see the effects of important design parameters on the net pumped volume, results of which were also presented and discussed. After the simulation studies, a working prototype pump with a 10.22 × 7.67 × 51.11 mm (W × H × L) was 3D printed. The experimental plan for the working prototype was discussed for further studies. The presented study lays the foundation for future studies where the pump size will be reduced to under 1 mm. The proposed micropump could potentially be used in a broad range of applications, such as an insulin dosing system for Type 1 Diabetic patients, artificial organs to transport blood, organ-on-chip applications, and so on.

Supercritical CO2 (sCO2) power cycles are promising next generation power technologies, holding a great potential in fossil fuel power plants, nuclear power production, solar power, geothermal power, and ship propulsion. To unlock the potential of sCO2 power cycles, technology readiness must be demonstrated on the scale of 10–600 MWe and at sCO2 temperatures and pressures of 350–700 °C and 20–30 MPa for nuclear industries. Amongst many challenges at the component level, the lack of suitable shaft seals for sCO2 operating conditions needs to be addressed for the next generation nuclear turbine and compressor development. In this study, we propose a novel Elasto-Hydrodynamic (EHD) high-pressure, high temperature, and scalable shaft seal for sCO2 turbomachinery that offers low leakage, minimal wear, low cost, and no stress concentration. The focus in this paper was to conduct a proof-of-concept study with the help of physics-based computer simulations. The results showed that the proof-of-concept study was successfully demonstrated, warranting further investigation. Particularly, it was interesting to note the quadratic form of the leakage rate, making its peak of m ˙ = 0.075 kg/s at Pin = 15 MPa and then decaying to less than m ˙ = 0.040 kg/s at Pin = 30 MPa, suggesting that the proposed seal design could be tailored further to become a potential candidate for the shaft seal problems in sCO2 turbomachinery.