This paper describes a new high-speed micro PIV technique for measuring both red blood cell velocity and plasma velocity to investigate rheology of blood flow in microcirculation. The measurement system consists of an epi-fluorescent microscope equipped with a high-speed camera with an image intensifier and two sets of colour filters. The technique was applied to in vitro blood flow through a micro round tube of 100 µm diameter. Velocity distributions of dyed red blood cells and plasma seeded with fluorescent particles were obtained separately. The obtained velocity distributions have a high spatial resolution of 9.0 µm × 2.2 µm and high temporal resolution of 6000 Hz.

Thermal striping tests in mixing tees with hot and cold water were conducted for three types of flow conjunctions in order to establish an evaluation method for high-cycle thermal fatigue of piping systems. Two kinds of examinations were planned. The preliminary tests were flow visualization tests carried out using acrylic pipes to obtain flow pattern characteristics and flow temperature fluctuations. The main tests were temperature fluctuation measurement tests carried out using metal pipes to evaluate the unsteady heat transfer coefficient based on measured temperature fluctuations of fluid and pipe wall. This paper reports visualization test results. The flow patterns were visualized by injection of methylene blue and compared with flow analysis results by the k-ε turbulence model. Temperature fluctuations of fluid 3mm from the inner pipe wall were measured with C-A thermocouples. Fundamental features such as locations with a large fluctuating temperature, the fluctuating temperature amplitude and its frequency were identified.

The interaction between chemical reactions and the flow field in microfluidic devices is investigated by a laser-induced fluorescence technique refined for use at microscopic spatial resolution. The pH distribution of chemically reacting flow at a Y-junction in a neutralization reaction in a microfluidic device is successfully visualized at a spatial resolution of 0.89 µm × 0.89 µm.

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