Numerical Examination of Heat Transfer Augmentation between the Plates with Square Cross-Sectional Ribs for the Staggered Arrangement

Results from large eddy simulation (LES) of fully developed flow in a staggered 45° ribbed duct are presented with rib pitch-to-height ratio P/e = 10 and a rib height to hydraulic diameter ratio e/Dh = 0.1. The nominal Reynolds number based on bulk velocity is 47,300. Mean flow and turbulent quantities, together with heat transfer and friction augmentation results are presented. The flow is characterized by a helical vortex behind each rib and a complementary cross-sectional secondary flow, both of which result from the angle of the rib with respect to the mean flow. Averaged velocity profiles at the duct center show excellent agreement with experiments and heat transfer predictions agree well with experiments. Turbulent kinetic energy, shear stress, and heat transfer augmentation ratios show a strong correlation to the rib vortex and the secondary flow. Overall, heat transfer is augmented by a factor of 2.3 compared with a smooth duct and matches experimental data within 2%.

Download Full-text

Experimental and numerical investigation of the heat transfer augmentation and pressure drop in simple, dimpled and perforated dimpled louver fin banks with an in-line or staggered arrangement

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2015.02.073 ◽

2015 ◽

Vol 82 ◽

pp. 194-205 ◽

Cited By ~ 21

Author(s):

Farhad Sangtarash ◽

Hossein Shokuhmand

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Numerical Investigation ◽

Heat Transfer Augmentation ◽

Staggered Arrangement

Download Full-text

Heat Transfer Augmentation in a Divergent Duct with Angled Ribs

International Journal of Air-Conditioning and Refrigeration ◽

10.1142/s2010132517500080 ◽

2017 ◽

Vol 25 (01) ◽

pp. 1750008

Author(s):

SooWhan Ahn ◽

MyungSung Lee

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Cross Section ◽

Test Section ◽

Average Nusselt Number ◽

Rectangular Duct ◽

Heat Transfer Characteristics ◽

Cross Sectional ◽

Circular Duct ◽

Heat Transfer Augmentation

Heat transfer characteristics in the rectangular divergent duct with parallel angled ribs are experimentally compared with the straight smooth circular duct. The ribs with four different parallel angles ([Formula: see text], 45[Formula: see text], 60[Formula: see text], and 90[Formula: see text]) are glued on the duct’s two opposite walls as well as on the duct’s one sided wall only, respectively. The 0.72[Formula: see text]-inclined walls are installed at the two opposite walls of the rectangular divergent duct. The test section of 1000[Formula: see text]mm long has the cross section of [Formula: see text][Formula: see text]mm2 at inlet and [Formula: see text][Formula: see text]mm2 at exit. The ribbed walls are manufactured with a rib height [Formula: see text][Formula: see text]mm and the ratio of rib spacing ([Formula: see text]) to height([Formula: see text]) [Formula: see text] 10. The main findings are summarized that the increase in the dimensionless Nusselt number for the flow attack angles can be seen in the order of 90[Formula: see text], 30[Formula: see text], 60[Formula: see text], and 45[Formula: see text] at the two opposite ribbed divergent wall ducts, in addition, the average Nusselt number in the divergent rectangular duct with two opposite ribbed walls is somewhat greater than in the ribbed straight cross-sectional rectangular duct.

Download Full-text

Assessment of Thermal Performance of Non-Conventional Grooved Stepped Shoe Ribs by CFD Technique

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.b3419.129219 ◽

2019 ◽

Vol 9 (2) ◽

pp. 75-82

Keyword(s):

Heat Transfer ◽

Thermal Performance ◽

Transfer Enhancement ◽

Heat Transfer Augmentation ◽

Thermal Enhancement ◽

Staggered Arrangement ◽

Extended Surface ◽

Computational Fluid Dynamics Cfd ◽

Conventional Type ◽

Thermal Enhancement Factor

In improvement of the thermal performance there is necessity of the heat transfer augmentation. Heat transfer enhancement can be achieved with enlarged or extended surface, impeded boundary level, augmentation in the turbulence etc. It is desired to keep the size of heat exchanger compact for better working conditions. In the proposed work, we made the Computational Fluid Dynamics (CFD) analysis of the non-conventional type of ribs. In this work the non-conventional Stepped grooved shoe shaped ribs were studied by changing its geometry parameters like rib height (15, 20,22mm), thickness of the rib (4, 5,10 mm), and the ratio between these entities. The numerical analysis was done to study change in rate of heat transfer and pressure drop. The effects of variation in staggered arrangements and truncation gap on thermal performance were also studied. It was observed that providing staggered arrangement with truncation gap of 20 mm gives the optimum value of thermal enhancement factor of 1.33.

Download Full-text

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200192 ◽

2020 ◽

Vol 92 (3) ◽

pp. 30901

Author(s):

Suvanjan Bhattacharyya ◽

Debraj Sarkar ◽

Ulavathi Shettar Mahabaleshwar ◽

Manoj K. Soni ◽

M. Mohanraj

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Thermal Performance ◽

Working Fluid ◽

The Novel ◽

Heat Exchanger Tube ◽

Heat Transfer Augmentation ◽

Corrugated Tube ◽

The Impact ◽

Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

Download Full-text