Hirofumi Tanigawa

Study on Shrinkage Deformation of Food in Microwave–Vacuum Drying

Drying shrinkage is an important problem in the food industry. Focusing on microwave–vacuum drying, we study the mechanism of deformation due to shrinkage of the food structure. A relationship between the strain and the water content is introduced for a finite element analysis. The temperature and water distributions are obtained by a finite difference method with the use of a variable permeability and diffusion coefficient depending on the water content. Comparisons with experimental data on radishes, carrots, and tofu indicate that the present model can express the deformation as well as the water content inside the materials.

Lattice Gas Analysis on Two-Phase Flow in Cathode of Polymer Electrolyte Fuel Cells

A numerical simulation system for the analysis of the transport phenomena inside the cathode electrode has been developed. The Lattice Gas Automaton (LGA) method is used for two-dimensional simulations to study the gas and water behaviors in the different type of flow passages. Three kinds of flow passage, the serpentine-type, the straight-type and the column-type are selected and their performances are compared. In this simulation, we shall consider the reaction between the proton and the oxygen as well as the water behaviors inside the separator flow-channel. The protons are supplied randomly at a constant rate on the flow-path surface, and the water is considered to be produced when the oxygen encounters to the proton. The transients of the reaction rate corresponding to the power generation are counted and the relation between the cell performance and the two-phase flow behaviors is investigated. The influence of hydrophobic and hydrophilic electrode on the cell performance is also studied. It is found that the serpentine-type flow is effective for the electric generation performance but induces the larger pressure loss. For the serpentine-type separator the hydrophobic electrode is effective for reducing the plugging phenomenon.Copyright

D-2-2 An Analysis and Verification of Moisture Transportation within Paper in the Fusing Process of Electrophotography

Paper curl is one of paper handling problems of printers and copiers. In the fusing process of electorophotography, the curl is generated by the temperature difference of paper surfaces. The temperature difference causes the moisture transport from the high-temperature side to the low-temperature side, and then the moisture content incline of the paper thickness direction causes the shrinkage difference that generates the curl. In the previous study, we proposed an analysis of the moisture transport in paper to predict the curl amount. This report shows the experimental method that measures the moisture distribution in paper by the electric resistance. And the experimental result indicates the validity of the analysis that calculates moisture distribution in paper.

Improvement of PEFC Cell Performance With a Movable Rib

Water management is very important in the development of the PEFC with high performance and high reliability. We found that the moisturizing effect in the straight-type channel is marked as compared with the serpentine-type channels, and the draining performance in the serpentine-type channel is better than that in the straight-type channel. Then, we have developed the movable rib which can change the position of the rib manually. Experimental study shows that the movable rib can control water behavior and can improve the cell performance.© 2011 ASME