Nobuo Mitsuishi

Bio: Nobuo Mitsuishi is an academic researcher from Kyushu University. The author has contributed to research in topics: Hydrogen & Inert gas. The author has an hindex of 10, co-authored 52 publications receiving 374 citations.

Non-newtonian fluid flow in an eccentric annulus

Abstract: Non-Newtonian fluid flow in an eccentric annulus was studied for high polymer aqueous solutions of CMC, HEC and MC. The macroscopic relations between the pressure drop and the flow rate were found to be in fairly good agreement with the results obtained by application of the conventional variational principle. Velocity profiles were measured by a hydrogen bubble method in which photographs were taken of the hydrogen bubbles. The authors observed very interesting secondary flows in the eccentric non-Newtonian fluid flow which may be due to the viscoelastic effect of the high polymer aqueous solution. The authors could not observe such secondary flows for non-Newtonian fluids in a concentric annulus or Newtonian fluids in an eccentric annulus. The authors present an equation giving the relation between the flow rate and the pressure drop for the flow of a non-Newtonian fluid in an eccentric annulus in terms of the experimental data for flow in a circular tube.

Heat transfer in agitated vessels with special types of impellers

Abstract: Studies on the rate of heat transfer in agitated vessels with special types of impellers were carried out. The impellers used were a double helical ribbon, a quadruple helical ribbon and a helical screw. The liquid media investigated were water, bitumen and aqueous glycerine solutions. Vessel-wall heat transfer coefficients were obtained for each impeller. For the helical screw, an off-centered system was studied and the impeller surface heat transfer coefficients were also obtained. Experimental data were correlated using dimensional analysis.

Absorption breakthrough of hydrogen isotopes in inert gas mixture and desorption characteristics with ZrNi alloy particle bed

Abstract: A metal particle packed bed is one of the most effective methods for the selective recovery of hydrogen isotopes in an inert gas such as argon or helium. An effective and convenient alloy might be ZrNi. ZrNi particles, 80–120 mesh, were packed in a column 20 mm in diameter, through which H 2 -Ar or H 2 -D 2 -Ar gas mixtures at 50 °C were passed. The absorption characteristics were obtained and the desorption rates of the hydrogen isotopes for the alloy were also obtained in flowing argon gas at 400, 600 and 800 °C. It was found that the absorption and desorption rates are very fast, large amounts can be absorbed and the activation of the ZrNi alloy is very easy. Since it is known that the isotopic differences between hydrogen and deuterium in absorption and desorption are very small, it can be concluded that the ZrNi alloy should serve as a good absorbent of the hydrogen isotopes, including tritium, at room temperature.

Membranes for hydrogen separation.

Abstract: 3.2. Preparation 4090 3.3. Intermediate Layers 4090 3.4. Support 4090 3.5. Modification 4091 3.5.1. Silica Membrane Modification 4091 3.5.2. Membrane Structure Modification 4092 3.6. Operational Stability 4092 4. Zeolite Membranes 4092 4.1. Membrane Growth Methods 4093 4.2. Permeation and Gas Transport 4093 4.3. Defect Site Diffusion/Nonzeolitic Pores 4094 4.4. Thin Films 4094 4.5. Zeolite Membrane Modification 4094 4.6. CO2 Sequestration in H2 Separations 4095 4.7. Manufacturing 4095 5. Carbon-Based Membranes 4096 5.1. Carbon Membrane Preparations 4097 5.2. Carbon Membrane Post-treatment 4097 5.3. Carbon Membrane Module Construction 4097 5.4. Selective Surface Flow Membranes 4097 5.5. Disadvantages of Carbon Membranes 4098 5.6. Molecular Sieving Carbon Membranes 4098 5.7. Carbon Nanotubes 4099 6. Polymer Membranes for H2 Separations 4100 6.1. Dense Polymeric Membranes 4100 6.2. Hydrogen Selective Polymeric Membranes 4101 6.3. H2 versus CO2 Selective Polymeric Membranes 4103

Hydrogen transport through tubular membranes of palladium-coated tantalum and niobium

Abstract: Palladium-based membranes have been used for decades in hydrogen extraction because of their high permeability and good surface properties and because palladium, like all metals, is 100% selective for hydrogen transport. We describe experiments with hydrogen-extraction membranes made of palladium-coated niobium and tantalum heat-exchanger tubes. The cost was about $45/ft of 3/8 in. tubular membrane, and the fluxes were as high as 0.001 47 mol/m2 s Pa1/2 at 420 °C. The main transport resistance is in the refractory metal substrate. Durability tests showed a 15% reduction in flux for 31 days of continuous membrane operation. Assuming durability is maintained for at least 1 year, this price and flux should allow competitive application for hydrogen recovery in petrochemical plants and for membrane reactors.

The axial flow of a Bingham plastic in a narrow eccentric annulus

Abstract: Analytical solutions are obtained by expanding in powers of δ, the ratio of the difference in radii of the bounding cylinders to their mean. The solution over most of the annulus is similar to that in a slot of uniform width, containing a central plug-like region over which the velocity is independent of the radial variable