Flow uniformity in oxygenators with different outlet port design.

This study reports on evaluation of the optimum design of a blood outlet port structure for providing uniform flow by visualizing the blood flow in an extracapillary membrane oxygenator. We tested a cylindrical type extracapillary membrane oxygenator, HPO-20. The HPO-20 has a tangential blood outlet port and is thus referred to as "Tangential HPO-20." We engineered "Vertical HPO-20" with a vertical blood outlet port by modifying the Tangential HPO-20. To visualize the blood-side flow, a total of 120 insulated copper-wire electrodes were placed in the "Tangential" and the Vertical HPO-20s. The test solution flow was visualized by the dimensionless fluid arrival time reaching each electrode. The test solution flow in the Tangential HPO-20 was not uniform, particularly at the outside blood channel. The flow was more uniform in the Vertical HPO-20. The blood flow in an extracapillary membrane oxygenator with a vertical blood outlet port is well distributed so that it produces more uniform blood flow than that with a tangential outlet port because of the small stagnation and reduced channeling.