Condensation heat transfer and pressure drop characteristics of R-134a flowing through dimpled tubes with different helical and dimpled pitches

บทความในวารสาร

ผู้เขียน/บรรณาธิการ

กลุ่มสาขาการวิจัยเชิงกลยุทธ์

ไม่พบข้อมูลที่เกี่ยวข้อง

รายละเอียดสำหรับงานพิมพ์

รายชื่อผู้แต่ง: Aroonrat K., Wongwises S.

ผู้เผยแพร่: Elsevier

ปีที่เผยแพร่ (ค.ศ.): 2018

วารสาร: International Journal of Heat and Mass Transfer (0017-9310)

Volume number: 121

หน้าแรก: 620

หน้าสุดท้าย: 631

จำนวนหน้า: 12

นอก: 0017-9310

eISSN: 1879-2189

URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040323732&doi=10.1016%2fj.ijheatmasstransfer.2018.01.001&partnerID=40&md5=c7803c8ed1400026693e550bddec6233

ภาษา: English-Great Britain (EN-GB)

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บทคัดย่อ

The heat transfer enhancement and pressure loss penalty of condensing refrigerant R-134a in dimpled tubes with different helical and dimpled pitches are experimentally investigated. The test section is a 1500-mm-long tube-in-tube heat exchanger placed horizontally. The inside and outside diameters of the inner tubes are 8.1 and 9.52 mm, respectively. One smooth tube and five dimpled tubes with different helical and dimpled pitches are tested. The experimental runs are done at saturated condensing temperatures ranging from 40 to 50 ฐC. The mass fluxes and heat fluxes vary from 300 to 500 kg/m2 s and from 10 to 20 kW/m2, respectively. The results show that the dimpled tubes yield higher heat transfer enhancement and pressure drop penalty compared to the smooth tube under the same operating condition. By decreasing helical and dimpled pitches, both the heat transfer coefficient and frictional pressure drop increase significantly. The maximum heat transfer coefficient and frictional pressure drop are achieved through the tube with the lowest helical and dimpled pitches (p = 5.08 mm, z = 3.24 mm) up to 88% and 630% higher than those of the smooth tube, respectively. The new correlations for predicting the Nusselt number and friction factor of R-134a condensing in dimpled tubes with different helical and dimpled pitches are proposed. ฉ 2018 Elsevier Ltd

คำสำคัญ

Dimpled tube