This paper describes the measurement of performance evaluation of rotational flow varying chamber size and Reynolds number. Through the experimental visualization of the flow rotation, the number and position of flow rotation in the $2{ imes}2$ microfluidic centrifuge were examined. At a chamber width of 250${mu}m$, single flow rotation was obtained over at a Reynolds number of 300, while at a chamber width of 500 ${mu}m$, single flow rotation did not appear. For performance evaluation, the intensity in microchamber was measured during 20 sec. At a chamber width of 250 ${mu}m$, performance of rotational flow increased as Reynolds number increased. However, the variation of intensity in microchamber remained unchanged at a chamber width of 500 ${mu}m$. The numerical analysis showed that the threshold centrifugal acceleration to obtain rotational flow for ejected particles was 200g.