Experimental Investigation on Flow Characteristics in a Tube-Bundle Channel

2012 ◽  
Author(s):  
Zhan Li ◽  
Guangyao Lu ◽  
Wenyuan Xiang
Keyword(s):  
Heat Exchange ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Circular Tube ◽  
Tube Bundle ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Flow Friction ◽  
Annular Channels ◽  
Flow Directions

Experiments were carried out to investigate the flow characteristics with/without heat exchange in vertical and inclined tube-bundle channels. In the experiments, the influences of flow directions and heat exchange upon the flow characteristics were studied. Experiments showed that the flow friction in tube-bundle channels had relations to the flow directions, and the liquid temperature difference at the inlet and outlet of tube-bundle channels. And these influences were comparatively obvious in the laminar flow regime. In the experiments, the transition from laminar to turbulent flow was carefully observed. The flow characteristics of single phase flow through tube-bundle channels were different from those in circular tubes and those in annular channels. The flow friction in tube-bundle channel is larger than that in normal circular tube. And the transition from laminar flow to turbulent flow in tube-bundle channel is different from that in normal circular tube. The influences of flow direction and heat exchange on the friction were also studied. The results were gained to provide the basis for the further investigations on the two-phase flow in tube-bundle channels.

Flow Characteristics of HFC-134a Gas-Liquid Two-Phase Flow Passing Through a Micro Circular Tube with Contraction and Expansion Sections

2019 ◽  
Vol 2019.68 (0) ◽  
pp. 409
Author(s):  
Toshiharu YAMADA ◽  
Naoki MARUYAMA ◽  
Toshiya MURAKAMI ◽  
Goki HIRATA ◽  
Hiroki TAKAGI ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Circular Tube ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase ◽  
Hfc 134A ◽  
Contraction And Expansion

scholarly journals Transition From the Turbulent to the Laminar Regime for Internal Convective Flow With Large Property Variations

1970 ◽  
Vol 92 (3) ◽  
pp. 506-512 ◽  
Author(s):  
C. W. Coon ◽  
H. C. Perkins
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Circular Tube ◽  
Reynolds Numbers ◽  
Bulk Temperature ◽  
Heating Rates ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
High Heating ◽  
Flow Situation

The results of a primarily experimental study of the transition from turbulent flow to laminar flow as a consequence of high heating rates are presented. Results are reported for hydrodynamically fully developed, low Mach number flows of air and helium through a vertical, circular tube. The electrically heated section was 100 diameters in length; entering Reynolds numbers ranged from 1700–40,000, and maximum wall-to-bulk temperature ratios reached 4.4. As a means of predicting the occurrence of a transition from turbulent flow to laminar flow, the experimental results are compared to the acceleration parameter suggested by Moretti and Kays and to a modified form of the parameter that is appropriate to a circular tube. It is suggested that the variable property turbulent flow correlations do not provide acceptable predictions of the Nusselt number and the friction factor if the value 4μq′′G2DTcp≃1.5×10−6 based on bulk properties, is exceeded for an initially turbulent flow situation. It is further suggested that Nusselt numbers and friction factors at locations down-stream from the point xDlaminar≃(2×10−8)(Tinlet)(Reb,inlet)2TwTbmax−1 for bulk temperatures in degrees Rankine may be obtained from the laminar correlation equations even though the flow is initially turbulent.

Heat and mass transfer from rotating cones

1963 ◽  
Vol 17 (1) ◽  
pp. 105-112 ◽  
Author(s):  
C. L. Tien ◽  
D. T. Campbell
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Heat And Mass Transfer ◽  
Flow Characteristics ◽  
Sublimation Rate ◽  
Semi Empirical ◽  
Good Agreement

Heat transfer by convection from isothermal rotating cones is investigated experimentally by measuring the sublimation rate from naphthalene-coated cones and using the analogy between heat and mass transfer. Measurements are made for a range of conditions from entirely laminar flow to conditions when the outer 70% of the surface area is covered by turbulent flow. Mass-transfer measurements for laminar flow over cones of vertex angles 180°, 150°, 120° and 90° are in good agreement with the theoretical prediction. For turbulent flow, experimental results for cones of the above vertex angles also agree very well with the semi-empirical analogy calculations for the disk case. A different heat- and mass-transfer relationship with the rotational Reynolds number is observed in the measurements on the 60° cone, and is believed to be due to a change of flow characteristics. The instability and the transition of flows over different cone models are also discussed.

Flow characteristics of single-phase flow in narrow annular channels

2008 ◽  
Vol 2 (4) ◽  
pp. 466-470 ◽  
Author(s):  
Heyi Zeng ◽  
Suizheng Qiu ◽  
Guanghui Su ◽  
Dounan Jia
Keyword(s):  
Single Phase ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Annular Channels

An Experimental and Numerical Study of Heat Transfer and Flow Characteristics of Laminar Flow in a Circular Tube With Wedge-Shaped Wavy-Tape Inserts

2018 ◽  
Author(s):  
Yunmin Liang ◽  
Peng Liu ◽  
Nianben Zheng ◽  
Feng Shan ◽  
Zhichun Liu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Circular Tube ◽  
Flow Characteristics ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Structures ◽  
Enhancement Ratio ◽  
Transfer Enhancement ◽  
Piv Measurements

In this study, a new type of tube inserts, named wedge-shaped wavy-tape insert, which is designed from bionics based on the movement of cuttlefish, is reported. The numerical simulation was carried out to investigate the effects of wedge-shaped wavy-tape insert arrangements on the heat transfer and flow characteristics of laminar flow in a circular tube under constant heat flux conditions. Details of the flow structures in the circular tube with wedge-shaped wavy-tape inserts which are arranged in same phase (S-type wavy tape) and different phase (D-type wavy tape) were presented and analyzed respectively. Then stereoscopic particle image velocimetry (Stereo-PIV) measurements on the flow structures were conducted to verify the numerical results. The flow structures obtained through simulations and PIV measurements agree well. It was observed that the arrangements of wedge-shaped wavy-tape inserts have a significant influence on the thermo-hydraulic performance. The average friction factor enhancement ratio f/f0 of D-type wavy tape were about 14%–20% lower than S-type wavy tape, but average heat transfer enhancement ratio Nu/Nu0 of D-type wavy tape were about 7%–14% higher than S-type wavy tape. The best performance evaluation criterion of D-type wavy tape could be improved to 3.02. The result shown the wedge-shaped wavy-tape insert is a promising technique for laminar convective heat transfer enhancement.

Numerical Study on Heat Transfer and Flow Characteristics for Laminar Flow in a Circular Tube with Swirl Generators

2018 ◽  
Vol 24 (3) ◽  
pp. 244-255 ◽  
Author(s):  
Yongli Sun ◽  
Guobin Wen ◽  
Xiaoming Xiao ◽  
Bohua Ren ◽  
Na Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Circular Tube ◽  
Numerical Study ◽  
Flow Characteristics

scholarly journals Unified Friction Formulation from Laminar to Fully Rough Turbulent Flow

2018 ◽  
Vol 8 (11) ◽  
pp. 2036 ◽  
Author(s):  
Dejan Brkić ◽  
Pavel Praks
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Pipe Flow ◽  
Flow Regimes ◽  
Hydraulic Model ◽  
Friction Model ◽  
Newtonian Fluids ◽  
Turbulent Regime ◽  
Flow Friction ◽  
Switching Functions

This paper provides a new unified formula for Newtonian fluids valid for all pipe flow regimes from laminar to fully rough turbulent flow. This includes laminar flow; the unstable sharp jump from laminar to turbulent flow; and all types of turbulent regimes, including the smooth turbulent regime, the partial non-fully developed turbulent regime, and the fully developed rough turbulent regime. The new unified formula follows the inflectional form of curves suggested in Nikuradse’s experiment rather than the monotonic shape proposed by Colebrook and White. The composition of the proposed unified formula uses switching functions and interchangeable formulas for the laminar, smooth turbulent, and fully rough turbulent flow regimes. Thus, the formulation presented below represents a coherent hydraulic model suitable for engineering use. This new flow friction model is more flexible than existing literature models and provides smooth and computationally cheap transitions between hydraulic regimes.

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