Mitsubishi Electric Corporation has announced the development of a millimeter-scale liquid flow technology using 10μm-diameter microbubbles as a driving source, eliminating the need for external pumps in water-cooling systems. The advancement, claimed as a world first by the company as of December 4, 2025, was achieved through joint research with the Suzuki & Namura Laboratory at Kyoto University.
The growing thermal output of electronic devices, especially in AI server environments, has increased the demand for high-efficiency water cooling systems. Microchannel-based cooling, which reduces the channel width to 100μm or less, offers improved efficiency but typically requires high-power external pumps to circulate liquid, raising concerns over energy consumption.
Kyoto University developed a method to induce flow using microbubbles generated by local heating and Marangoni forces, which result from temperature gradients at vapor-liquid interfaces. Mitsubishi Electric applied this approach to a microchannel, achieving a flow speed of 100μm/s in a 3mm x 3mm square channel with a cross-section of 100μm x 400μm, without any external pump. Flow performance was later improved to 440μm/s by optimizing the bubble arrangement and channel design.
The company aims to further develop this technology to enhance the energy efficiency and performance of future cooling systems in support of carbon neutrality goals.
This research has been published in Applied Physics Letters, an international journal by the American Physical Society.
