ee phase flow measurement based on elbow tube and conductance ............................................................................................ 68 5.6 Summary of the Chapter.......................................................................... 72 Chapter 6 Study on measure me thods of water content ratio ................... 73 6.1 Study of capacitance and short wave methods for water content ratio..... 73 6.1.1 Model of capacitance and short wave methods for two phase flow.... 73 6.1.2 Thoery formula of capacitance an d short wave method s for three phase flow............................................................................................................ 75 6.2 Study of γ ray for water content ratio measurement................................. 77