The effects of variable distribution coefficients on the separation efficiency in zone refining processes have been simulated by operating liquid analog simulators. During the operation processes of liquid analog simulators, properly adjusting the area of zone tube along the operating procedure to simulate the operation with variable distribution coefficients, will obtain the liquid level redistribution in ingot tubes, resulting in the simulation of separation processes. The structure, operation and mathematical representation of liquid analog simulators are discussed. Performance of the proposed multipass zone-refining simulators are in excellent agreement with numerical solutions.