<link rel="stylesheet" href="styles.cf390c6bfbe7555f.css">

學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Author: search.filters.author.Liaw, Jane-SunnHas files: Yes

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item type:Item,
    Compound Heat Transfer Enhancement of Wavy Fin-and-Tube Heat Exchangers through Boundary Layer Restarting and Swirled Flow
    (2018-08-01)
    Sadeghianjahromi, Ali
    ;
    Kheradmand, Saeid
    ;
    Nemati, Hossain
    ;
    Liaw, Jane-Sunn
    ;
    Wang, Chi-Chuan
    This study performs a 3D turbulent flow numerical simulation to improve heat transfer characteristics of wavy fin-and-tube heat exchangers. A compound design encompassing louver, flat, and vortex generator onto wavy fins can significantly enhance the heat transfer performance of wavy fin-and-tube heat exchangers. Replacement of wavy fins around tubes with flat fins is not effective as far as the reduction of thermal resistance is concerned, although an appreciable pressure drop reduction can be achieved. Adding two louvers with a width of 8 mm to the flat portion can reduce thermal resistance up to 6% in comparison with the reference wavy fin. Increasing the louver number and width can further decrease the thermal resistance. Also, it is found that the optimum louver angle is equal to the wavy angle for offering the lowest thermal resistance. Therefore, compound geometry with three louvers, a width of 12 mm, and the louver angle being equal to wavy angle with waffle height to be the same as fin pitch of the reference wavy fin has the most reduction in thermal resistance of 16% for a pumping power of 0.001 W. Adding punching longitudinal vortex generators on this compound geometry can further decrease thermal resistance up to 18%.
  • Thumbnail Image
    Item type:Item,
    Airside Performance of H-Type Finned Tube Banks with Surface Modifications
    (2019-02-02)
    Bhale, Pradhyumn
    ;
    Kaushik, Mrinal
    ;
    Liaw, Jane-Sunn
    ;
    Wang, Chi-Chuan
    ;
    機械工程學系
    The present study numerically investigates some novel modifications to augment the performance of the H-type finned tube banks, which are widely used in waste heat recovery in industries. The imposed modifications upon the original H-type finned tube banks include the following: (1) Design 1 contains some triangular cuts at the edge of the original rectangular fin; (2) Design 2 modifies the original rectangular geometry into a trapezoid shape; (3) Design 3 renders the original rectangular cross-section fin thickness into trapezoid cross-section; and (4) Design 4 changes the original rectangular shape into a circular shape. Based on the simulations, it is found that Design 1 shows barely any improvements in the heat transfer performance and surface area reduction. Design 2 can provide some weight saving and surface area reduction at a slightly inferior heat transfer performance. Design 3 can offer up to 14% improvements in the overall heat transfer performance without any pumping power penalty. Yet, Design 4 provides the maximum weight saving as compared to the original reference case. With 3-9% lesser surface area than the reference case, Design 4 still offers marginally higher heat transfer performance.
  • Thumbnail Image
    Item type:Item,
    Effect of partial bypass on the heat transfer performance of dehumidifying coils
    (2014-11-01)
    Wang, Chi-Chuan
    ;
    Cheng, Yu-Cheng
    ;
    Liaw, Jane-Sunn
    ;
    Tseng, Chih-Yung
    ;
    機械工程學系
    This study extends a so called "partial bypass" concept to dehumidifying fin-and-tube heat exchangers. Tests are performed for a 2-row and 4-row fin-and-tube heat exchangers having plain fin configuration. The inlet dry bulb temperature is fixed at 25 degrees C while the inlet relative humidities are 50% and 80%, respectively. Test results showed that for a 2-row coil under RH = 50%, the corresponding heat transfer augmentation ratio (Q(R)) and pressure penalty ratio (P-R) decrease with the rise of bypass ratio (BR). At a smaller frontal velocity, the regime of appropriate bypass ratio where Q(R) > 1 and P-R < 1 is more apparent. The effect of partial bypass decreases as the velocity increases. As the velocity gets close to 2 m s(-1), it shows that the performance at high bypass ratio becomes more efficient. At the same time, when bypass ratio becomes lager, the tendency of the decreasing of Delta P is more drastic than the decreasing of Q. Nevertheless, not for all the cases that the performances get better as the bypass ratio increases. For V-fr = 4 m s(-1), the experiment results show that the overall effect is less efficient\' than at V-fr = 2 m s(-1). The major reason is caused by the flow pattern. The rise of bypass airflow is quite large which may act as an air curtain to distort the main airflow, and result in higher pressure drop. This implies that the design of the bypass design is quite imperative in the practice of real applications. For a 4-row heat exchanger, the experiment data of QR and PR for the 4-row coil performs better than a 2-row coil. (C) 2014 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item type:Item,
    Airside performance of herringbone wavy fin-and-tube heat exchangers - data with larger diameter tube
    (2011-02-01)
    Wang, Chi-Chuan
    ;
    Liaw, Jane-Sunn
    ;
    Yang, Bing-Chwen
    ;
    機械工程學系
    ;
    Department of Mechanical Engineering
    This study examines the airside performance of the wavy fin-and-tube heat exchangers having a larger diameter tube (D(c) = 16.59 mm) with the tube row ranging from 1 to 16. It is found that the effect of tube row on the heat transfer performance is quite significant, and the heat transfer performance deteriorates with the rise of tube row. The performance drop is especially pronounced at the low Reynolds number region. Actually more than 85% drop of heat transfer performance is seen for F(p) similar to 1.7 mm as the row number is increased from 1 to 16. Upon the influence of tube row on the frictional performance, an unexpected row dependence of the friction factor is encountered. The effect of fin pitch on the airside performance is comparatively small for N = 1 or N = 2. However, a notable drop of heat transfer performance is seen when the number of tube row is increased, and normally higher heat transfer and frictional performance is associated with that of the larger fin pitch. (C) 2010 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item type:Item,
    Air-side performance of herringbone wavy fin-and-tube heat exchangers under dehumidifying condition - Data with larger diameter tube
    (2012-05-01)
    Wang, Chi-Chuan
    ;
    Liaw, Jane-Sunn
    ;
    機械工程學系
    ;
    Department of Mechanical Engineering
    This study examines the airside performance of the herringbone wavy fin-and-tube heat exchangers in dehumidifying condition having a larger diameter tube (D-c = 16.59 mm) with the tube row ranging from 2 to 12. Test results are compared to that of dry conditions and plain fin geometry. Upon the influence of surface condition (dry or wet) on the heat transfer performance, the heat transfer performance in dehumidifying condition normally exceeds that in dry condition, and is more pronounced with the rise of tube row or reduction of fin pitch. By contrast, it is found that the heat transfer coefficient for plain fin geometry in dehumidifying condition is slightly lower than that in dry condition. The pressure drops in wet condition is much higher than that in dry condition. However, the difference in pressure drop amid dry and dehumidifying condition for wavy fin configuration is less profound as that of plain fin geometry. (C) 2012 Elsevier Ltd. All rights reserved.