An experimental study on the characteristics of heat transfer on the turbulent round impingement jet according to the inclined angle of convex surface using the liquid crystal transient method

Lim, Kyoung-Bin; Lee, C.H.; Sung, Nak Won; Lee, S.H.

doi:10.1016/j.expthermflusci.2006.07.005

Cited by 15 publications

(7 citation statements)

References 10 publications

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“…As a result, much of the prior researches have provided comprehensive information in terms of heat transfer efficacies through CFD works and experimental means, such as in the works of Chen (2012), Yang et al (2011), Fenot et al (2008, Chander and Ray (2007) and Lim et al (2007). This also indicates that the basic flow dynamics of circular jet impinging upon curved surfaces are comparatively less well understood especially in terms of their resultant vortex structures and dynamic flow behaviour, while their flat surface counterparts have been comprehensively studied, such as investigations carried out by Fairweather and Hargrave (2002a, b), Duda et al (2008) and EI Hassan et al (2012).…”

Section: Introductionmentioning

confidence: 99%

A DPIV study on the effects of separation distance upon the vortical behaviour of jet–cylinder impingements

Long

New

2015

Exp Fluids

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Section: Introductionmentioning

confidence: 99%

A DPIV study on the effects of separation distance upon the vortical behaviour of jet–cylinder impingements

Long

New

2015

Exp Fluids

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“…At 6 = 0deg (the normal im pinging position), the local heat transfer distribution on the large cylinder (D/Dj= 10.0) follows that on the flat plate, including the consistent lateral location of the local minimum at s/Dj = 1.5 and the second peak at s/Dj = 2.0 ( Fig. 11(a)) [1,[9][10][11]13,29]. As the jet is inclined to 6 = 45 deg, the difference in the local heat transfer on the downhill side becomes evident: a higher heat transfer on the flat plate and a lower heat transfer on a cylinder with a smaller DIDj ratio as plotted in Fig.…”

Section: 41mentioning

confidence: 97%

“…Among these few studies on the inclined jet, Lim et al [29] measured local heat transfer coefficients on a hemispherical convex surface with a round oblique impinging jet for 2.0 < z/D, < 10.0 and 0 deg<9<40deg at a fixed jet Reynolds number of 23,000. Here, 9 denotes the angle that is inclined from the axis normal to the tangent of the curved surface at its geometric stagnation point.…”

Section: F Ig 3 S C H E M a T Ic S O F ( A ) T E S T S E T U P Fo Rmentioning

confidence: 99%

Heat Transfer Characteristics of an Inclined Impinging Jet on a Curved Surface in Crossflow

Wang

Yan

et al. 2014

Journal of Heat Transfer

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This study reports on heat transfer characteristics on a curved surface subject to an inclined circular impinging jet whose impinging angle varies from a normal position 9 = 0 deg to 9 = 45 deg at a fixed jet Reynolds number of Rej = 20,000. Three curved surfaces having a diameter ratio (DIDfl of 5.0, 10.0, and infinity (i.e., a flat plate) were selected, each positioned systematically inside and outside the potential core of jet flow where Dt is the circular jet diameter. Present results clarify similar and dissimilar local heat transfer characteristics on a target surface due to the convexity. The role of the potential core is identified to cause the transitional response of the stagnation heat trans fer to the inclination of the circular jet. The inclination and convexity are demonstrated to thicken the boundary layer, reducing the local heat transfer (second peaks) as opposed to the enhanced local heat transfer on a flat plate resulting from the increased local Reynolds number.

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“…Stimulus is the quantity, property, or condition that is sensed and converted into definite (mostly electrical) signal [1][2][3]. It was also applied for registration, visualization, and measurement of air flows that modify the temperature fields [7][8][9]. It is based on a strong sensitivity of the selective reflection spectra to temperature variations that makes it possible to visualize temperature fields [4].…”

Section: Liquid Crystals As Sensors Of Mechanical Perturbations: Physmentioning

confidence: 99%

Liquid Crystal Sensors

2009

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The main aim of this chapter is to demonstrate a principal possibility of elaboration of liquid crystal sensors of mechanical perturbations based on the results of basic investigations of linear and nonlinear phenomena in shear flows of liquid crystals (Chapter 3).This chapter is organized as follows. First, we will define the physical background of sensor applications of liquid crystals and discuss the main parameters of mechanooptical effects in Poiseuille flows of liquid crystals, important for practice and optimization of these parameters. Then, we will concentrate on some types of liquid crystal sensors proposed for sensing of steady and low-frequency mechanical forces and motion. In particular, we will consider the sensors of the pressure difference, acceleration, vibration, and inclination. We will consider the possible construction of such devices and estimate their technical parameters. The use of liquid crystal sensors for the control of liquid and gas flows will be discussed too. Finally, we will describe some experimental results of acoustooptical effects on liquid crystals at additional action of electric and magnetic fields. The latter can be important for the elaboration of electrically controlled liquid crystal sensors, which can be used in detection and visualization of high-frequency (ultrasonic) vibrations. Liquid Crystals as Sensors of Mechanical Perturbations: Physical Background and Main CharacteristicsLiquid crystals can be considered a very promising material for sensor applications. It is determined by high sensitivity of liquid crystal media to the action of different factors of physical (or chemical) nature. In general, a sensor is often defined as a device that receives and responds to a signal or stimulus [1]. Stimulus is the quantity, property, or condition that is sensed and converted into definite (mostly electrical) signal [1][2][3]. Sensing and visualization of temperature fields via cholesteric liquid crystals can be considered as the most traditional sensor application of liquid crystals. It is based on a strong sensitivity of the selective reflection spectra to temperature variations that makes it possible to visualize temperature fields [4]. Such possibility is traditionally used in biomedical applications of liquid crystals [5,6] for the diagnostics Liquid Crystals: Viscous and Elastic Properties

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An experimental study on the characteristics of heat transfer on the turbulent round impingement jet according to the inclined angle of convex surface using the liquid crystal transient method

Cited by 15 publications

References 10 publications

A DPIV study on the effects of separation distance upon the vortical behaviour of jet–cylinder impingements

A DPIV study on the effects of separation distance upon the vortical behaviour of jet–cylinder impingements

Heat Transfer Characteristics of an Inclined Impinging Jet on a Curved Surface in Crossflow

Liquid Crystal Sensors

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