A simple method for predicting bulk temperature from tube wall temperature with uniform outside wall heat flux

Forced convection heat transfer in fully developed laminar flow in transversely corrugated tubes is investigated for nonuniform but constant wall heat flux as well as for constant wall temperature. Epitrochoid conformal mapping is used to map the flow domain onto the unit circle in the computational domain. The governing equations are solved in the computational domain analytically. An exact analytical solution for the temperature field is derived together with closed form expressions for bulk temperature and Nusselt number for the case of the constant heat flux at the wall. A variable coefficient Helmholtz eigenvalue problem governs the case of the constant wall temperature. A novel semi-analytical solution based on the spectral Galerkin method is introduced to solve the Helmholtz equation. The solution in both constant wall heat flux and constant wall temperature case is shown to collapse onto the well-known results for the circular straight tube for zero waviness.

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Effect of Gas-Side Physical-Property Variations on the Heat Transfer to a Bank of Tubes in Cross-Flow

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1975_189_068_02 ◽

1975 ◽

Vol 189 (1) ◽

pp. 581-587 ◽

Cited By ~ 4

Author(s):

R. J. Preece ◽

J. Lis ◽

J. A. Hitchcock

Keyword(s):

Heat Transfer ◽

Physical Properties ◽

Wall Temperature ◽

Tube Wall ◽

Cross Flow ◽

Physical Property ◽

Bulk Temperature ◽

Dimensionless Groups ◽

Tube Wall Temperature ◽

Conventional Type

The paper describes a study of the effect of variations in the physical properties of a gas caused by large gas-to-wall temperature differences on the convective heat transfer to plain tubes in cross-flow. The experiments were carried out in air at bulk air-to-wall temperature differences ranging from 109 K to 397 K with two levels of tube-wall temperature, 40°C or 120°C. The bulk Reynolds number ranged from 104 to 2.65 times 104. It was found that the variation in physical properties could be accommodated by evaluating all of these properties in the dimensionless groups of the conventional type of correlation at the air bulk temperature.

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Influence of Gas-to-Wall Temperature Ratio on By-Pass Transition

Volume 2A: Turbomachinery ◽

10.1115/gt2017-63524 ◽

2017 ◽

Cited By ~ 1

Author(s):

Tânia S. Cação Ferreira ◽

Tony Arts

Keyword(s):

Heat Flux ◽

Wall Temperature ◽

Analog Circuits ◽

Guide Vane ◽

Operating Conditions ◽

Wall Heat Flux ◽

Bypass Transition ◽

Temperature Ratio ◽

Isentropic Compression ◽

Pressure Transducers

An investigation of thermal effects on bypass transition was conducted on the highly-loaded turbine guide vane LS89 in the short-duration isentropic Compression Tube (CT-2) facility at the von Karman Institute for Fluid Dynamics (VKI). Measurements from high response surface-mounted thin films coupled with analog circuits provided the time-resolved wall heat flux history whereas pneumatic probes, differential pressure transducers and thermocouples allowed the accurate definition of the inlet and outlet flow conditions. The gas-to-wall temperature ratio, ranging from 1.11 to 1.55, was varied by changing the inlet total temperature. The isentropic exit Mach number ranged from 0.90 to 1.00 and the global freestream turbulence intensity value was set at 0.8, 3.9 and 5.3%. The isentropic exit Reynolds number was kept at 106. The onset of transition was tracked through the wall heat flux signal fluctuations. Within the present operating conditions, no significant effect of the gas/wall temperature ratio was put in evidence. At the present (design) transonic exit conditions, the local free-stream pressure gradient appears to remain the main driver of the onset of transition. A wider range of operating conditions must be considered to draw final conclusions.

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An Experimental Investigation of Flow Boiling Characteristics in a Single Transparent Heated Microtube

ASME 2009 InterPACK Conference, Volume 2 ◽

10.1115/interpack2009-89142 ◽

2009 ◽

Author(s):

Osamu Kawanami ◽

Shih-Che Huang ◽

Kazunari Kawakami ◽

Itsuro Honda ◽

Yousuke Kawashima ◽

...

Keyword(s):

Heat Flux ◽

Wall Temperature ◽

Mass Velocity ◽

Tube Wall ◽

Flow Boiling ◽

High Mass ◽

Test Fluid ◽

High Heat Flux ◽

Gold Plating ◽

Heated Tube

In the present study, flow boiling in a transparent heated microtube having a diameter of 1 mm was investigated in detail. The transparent heated tube was manufactured by the electroless gold plating method. The enclosed gas-liquid interface could be clearly recognized through the tube wall, and the inner wall temperature measurement and direct heating of the film were simultaneously conducted by using the tube. Deaerated and deionized water that was subcooled temperature of 15 K was used as a test fluid, and constant and stable mass velocities of 50, 100, and 200 kg/m2s were provided by using a twin plunger pump. Among our experimental results, a vapor bubble grew up in a direction opposite the flow at a low heat flux and low mass velocities; however, this flow pattern was not observed at a high mass velocity of 200 kg/m2s. Under the conditions of G = 50 kg/m2s and high heat flux, the liquid film surrounding an elongated bubble near the heated tube wall occasionally thickened partially. The inner wall temperature exhibited large random oscillations in this regime; however, the visual observation revealed that dry-patches did not occur. The mass velocity had a negligible effect on the boiling heat transfer except in the counter-growth bubble flow regime.

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Thermal response of an unsteady laminar boundary layer on a flat plate due to step changes in wall temperature and in wall heat flux

Computer Methods in Applied Mechanics and Engineering ◽

10.1016/0045-7825(73)90005-4 ◽

1973 ◽

Vol 2 (3) ◽

pp. 323-338 ◽

Cited By ~ 4

Author(s):

Tuncer Cebeci ◽

J. Bard

Keyword(s):

Boundary Layer ◽

Heat Flux ◽

Flat Plate ◽

Laminar Boundary Layer ◽

Wall Temperature ◽

Thermal Response ◽

Wall Heat Flux

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An Improved Model to Study the Density Wave Oscillation in Tubes by Using Frequency Domain Method

Volume 2A: Thermal Hydraulics ◽

10.1115/icone22-30343 ◽

2014 ◽

Author(s):

Yifan Zhang ◽

Huixiong Li ◽

Tai Wang ◽

Weiqiang Zhang ◽

Tianyou Sheng

Keyword(s):

Heat Flux ◽

Frequency Domain ◽

Present Model ◽

Heat Storage ◽

Tube Wall ◽

Density Wave ◽

Wall Heat Flux ◽

Frequency Domain Method ◽

Conventional Model ◽

Domain Method

Density Wave Oscillation (DWO) in tubes was usually studied by using the frequency domain method. However, in the conventional model, the heat storage of wall metal was usually neglected to simplify the complex solving process of transfer functions, which might cause unreasonable results when the tube wall had a thick wall or complex geometry structures. Hence, in the present paper, an improved mathematical model was proposed based on the frequency domain theory to theoretically study the DWO in tubes. The present model was an improvement of the conventional model. The most notable improvement in the present model was that the heat storage of the tube wall metal, the internal wall heat flux and the external wall heat flux were all considered as dynamic parameters. Based on the improvement, the prediction of the DWO in tubes by using the present model might be more accurate and reasonable than that by using the conventional model, and this was proved by the comparison of the results obtained with the two models to the experimental results gained from literature. In the present study, it was shown that both the present model and the conventional model could predict the DWO in tubes well when the tube wall was thin, and it was also found that the present model was more appropriate than the conventional model when the tube wall was thick. Both the thickness of the tube wall and the specific heat of tube wall metal play negative roles in the system stability.

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