Augmented heat transfer with intersecting rib in rectangular channels having different aspect ratios

Chung, Hyo-Sang; Park, Jun Su; Park, Sehjin; Choi, Seok Min; Rhee, Dong-Ho; Cho, Hyung Hee

doi:10.1016/j.ijheatmasstransfer.2015.04.033

Cited by 52 publications

(9 citation statements)

References 24 publications

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“…In the geometry of undulated plate, a combination of plate angle and undulation angle functions as a rib in a channel. These results are similar to those of previous studies conducted by Cho et al [30][31][32][33][34][35]. The high value can be understood by analyzing the turbulence intensity in Figure 5.…”

Section: Thermal-fluid Characteristicssupporting

confidence: 91%

Optimization of the Heating Element in a Gas-Gas Heater Using an Integrated Analysis Model

et al. 2017

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Gas-gas heaters (GGHs) are used to reheat gases through desulfurization in coal-fired power plants to reduce low-temperature corrosion and white smoke. Wrinkled heating elements are installed inside the GGH to perform effective heat exchange. An optimization study of the heating element shape was conducted to reduce the differential pressure effectively and improve performance. An integrated analysis model was applied. Based on actual operational data, a computational fluid dynamic analysis was conducted on the L-type heating element and GGH system. The experiments applied the optimal latin hypercube sampling method, and numerical analysis was performed for each sample. Based on the response surface, the result of the sample was optimized through the pointer algorithm. For the integrated analysis model, validation was performed by comparison with the actual operational data, and the thermal-fluid characteristics of the heating element and GGH system were analyzed to set three parameters: plate angle, undulated angle, and pitch 1. From the optimization result, increases in the undulated angle and pitch 1 reduce the pressure drop by widening the heating element cross section. By increasing the plate angle, the heat transfer area is secured and the reduced heat transfer coefficient is compensated, improving the GGH performance.

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Section: Thermal-fluid Characteristicssupporting

confidence: 91%

Optimization of the Heating Element in a Gas-Gas Heater Using an Integrated Analysis Model

et al. 2017

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“…where q is the wall heat flux, and T w and T f are the wall temperature and fluid temperature, respectively. The friction is defined as [27]:…”

Section: Grid Schemementioning

confidence: 99%

Effects of Channel Outlet Configuration and Dimple/Protrusion Arrangement on the Blade Trailing Edge Cooling Performance

2019

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The trailing edge regions of high-temperature gas turbine blades are subjected to extremely high thermal loads and are affected by the external wake flow during operation, thus creating great challenges in internal cooling design. With the development of cooling technology, the dimple and protrusion have attracted wide attention for its excellent performance in heat transfer enhancement and flow resistance reduction. Based on the typical internal cooling structure of the turbine blade trailing edge, trapezoidal cooling channels with lateral extraction slots are modeled in this paper. Five channel outlet configurations, i.e., no second passage (OC1), radially inward flow second passage (OC2), radially outward flow second passage (OC3), top region outflow (OC4), both sides extractions (OC5), and three dimple/protrusion arrangements (all dimple, all protrusion, dimple–protrusion staggered arrangement) are considered. Numerical investigations are carried out, within the Re range of 10,000–100,000, to analyze the flow structures, heat transfer distributions, average heat transfer and friction characteristics and overall thermal performances in detail. The results show that the OC4 and OC5 cases have high heat transfer levels in general, while the heat transfer deterioration occurs in the OC1, OC2, and OC3 cases. For different dimple/protrusion arrangements, the protrusion case produces the best overall thermal performance. In conclusion, for the design of trailing edge cooling structures with lateral slots, the outlet configurations of top region outflow and both sides extractions, and the all protrusion arrangement, are recommended.

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“…Many of them deal with the influence of the shape or the arrangement of single passive inserts inside the channels, using experimental or numeric methods. Most of those investigations are focused on the fully turbulent flow regime, as the Reynolds number is higher than Re > 10,000 [1][2][3][4]. Various geometrical shapes of passive inserts have been investigated in the past.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Heat Transfer Enhancement with Passive Inserts in Flat Tubes in due Consideration of an Efficiency Assessment

Bertsche

Knipper²,

Meinicke

et al. 2022

Fluids

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This paper presents results of an experimental investigation on pressure drop and heat transfer for a wide range of Reynolds and Prandtl numbers ranging from 8 < Pr < 60 and 40 < Re < 3500, for flat tubes without and with passive inserts. For three different kinds of passive insert designs, the impact on heat and momentum transfer due to coaction of the total set of passive inserts with different shape and amount was investigated. Experimental results were analyzed regarding two main aspects: Heat transfer mechanisms and pressure drop induced by friction and form drag forces due to the presence of different shapes. After heat and momentum transfer mechanisms for each passive insert design were analyzed, heat transfer and pressure drop enhancement were compared to each other, leading to an efficiency discussion. Different concepts for efficiency evaluation, which are cited in literature, were applied to the presented experimental data. Pros and cons of the different concepts are discussed. Finally, we propose an equation for evaluation of total performance, which fully respects the energetic and exergetic aspects of heat transfer and pressure drop enhancement.

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Augmented heat transfer with intersecting rib in rectangular channels having different aspect ratios

Cited by 52 publications

References 24 publications

Optimization of the Heating Element in a Gas-Gas Heater Using an Integrated Analysis Model

Optimization of the Heating Element in a Gas-Gas Heater Using an Integrated Analysis Model

Effects of Channel Outlet Configuration and Dimple/Protrusion Arrangement on the Blade Trailing Edge Cooling Performance

Experimental Investigation on Heat Transfer Enhancement with Passive Inserts in Flat Tubes in due Consideration of an Efficiency Assessment

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