Oxygen Supply and Recovery System for Closed Environment such as a Space Station.-Fromation of blue-green algae Cultivated Field under Microgravity-

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From the viewpoint of oxygen supply and recovery in the closed environment such as a space station, the formation possibility of the blue green algae cultivated field under microgravity was experimentally investigated.The 10m-high drop tower at the Hokkaido National Industrial Research Institute (HNIRI) and the 500m-high drop tower at the Japan Microgravity Center (JAMIC) were used to create the microgravity environment. The HNIRI and the JAMIC drop towers provided a microgravity period of approximately l.2s (g_2/g_0<10^<-3>G) and 10s (g_2/g_0<10^<-4>G), respectively. The dimensions of the experimental setup at the HNIRI drop tower are 600Dx425Wx910H.The dimensions of the experimental setup at the JAMIC drop tower are 870Dx425Wx918H and 425Dx425Wx918H.The diameter and volume of reactor ranged from 0.055 to 0.13m and from 8.5x105 to l.3xl0-3 m3, respectively. An 8mm video camera was fixed on the lateral part of the reactor and was used to observe and record the change in the gas-liquid … More interface during the drop. The character generator was used to record the drop time on the tape.A cylindrical vessel partially filled with water was rotated to form low centrifugal force(approximately, 10^<-1>G at the wall side of the vessel) under microgravity created in the drop tower. The interface shape of the gas-liquid systems in a rotating speed of the vessel was observed and recorded. The effects of diameter and rotating speed of vessel, liquid volume, liquid viscosity and surface tension on the interface shape were investigated. Hollow flow formation was considered to be suitable for oxygen supply and recovery system that an air phase was located in the center of the vessel and the air-water interface contacted with both the bottom and the top-cover of the vessel. The possible and/or impossible regions to form the hollow flow in were dearly divided in the formation map for the microgravity gas-liquid systems in a rotating vesseL The map indicates that the formation of the hollow flow under microgravity could be predicted by the Weber number and the ratio of the liquid/vessel volume. We concluded from the formation map that the optimum condition was obtained when We=8 and V_1/V_T=0.80. because a power consumption, namely, the rotating speed of the vessel, became a minimum. Less