Abstract: As shown in Figs. 1a and 1c, the pressure at the inlet increases by about 50 Pa due to the blocking of the first few rows of tube bundles. To better discuss the heat transfer of each tube, the tube bundle is divided into 10 zones (Condensation01‍–‍Condensation10) from top to bottom, among which Condensation10 is the air-cooling zone. Detailed description can be seen in Section S2 of the ESM. The air-cooling zone is the last section where the water vapor flows out of the tube bundle, and the air extraction port is located in it. Directly upon entering the Condensation01 zone, some of the steam drops in pressure due to condensation. Another part of the steam enters the channels on both sides, and gradually enters the Condensation02‍–Condensation08 zones obliquely downward to condense; then, the pressure gradually decreases by about 100 Pa. Due to the bottom wall being blocked, the pressure in the lower half of the Condensation09 zone is slightly increased, and this phenomenon is more significant for non-uniform tube-bundle arrangements. In the air-cooling zone (Condensation10), the air and uncondensed steam are drawn out at the outlet by the exhaust fan, and the pressure drop is relatively large (about 200 Pa). Regarding the velocity distribution shown in Figs. 1b and 1d, the highest velocity is located at the central channel with different tube-bundle arrangements. Specifically, the highest velocity for the uniform tube-bundle arrangement is about 170 m/s, while it is about 180 m/s for the non-uniform tube-bundle arrangement. The velocity in the channels on both sides decreases gradually and decreases further once the steam passes through the microchannel. The velocity decreases again to 40 m/s at the bottom of the condenser (Condensation09), and the velocity between the tubes in Condensation01‍–‍Condensation09 zones is about 30 m/s. The velocity at Condensation10 in the air-cooling zone is about 70 m/s.

1000MW级凝汽器的壳侧流场的一种新的数值模拟方法

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