scholarly journals Applications of variable property heat-transfer and friction equations to rocket nozzle coolant passages and comparison with nuclear rocket test results

1970 ◽  
Author(s):  
M. TAYLOR
Keyword(s):  
Heat Transfer ◽  
Test Results ◽  
Rocket Nozzle ◽  
Variable Property ◽  
Nuclear Rocket

Natural-Convection Heat Transfer in Liquids Confined by Two Horizontal Plates and Heated From Below

1959 ◽  
Vol 81 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Samuel Globe ◽  
David Dropkin
Keyword(s):  
Heat Transfer ◽  
Silicone Oil ◽  
Convection Heat Transfer ◽  
Test Results ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Silicone Oils ◽  
Prandtl Numbers ◽  
The Relationship ◽  
Rayleigh Numbers

This paper presents results of an experimental investigation of convective heat transfer in liquids placed between two horizontal plates and heated from below. The liquids used were water, silicone oils of 1.5, 50, and 1000 centistoke kinematic viscosities, and mercury. The experiments covered a range of Rayleigh numbers between 1.51(10)5 and 6.76(10)8. and Prandtl numbers between 0.02 and 8750. Tests were made in cylindrical containers having copper tops and bottoms and insulating walls. For water and silicone oils the container was 5 in. in diam and 2 in. high. For mercury, two containers were used, both 5.28 in. in diameter, but one 1.39 in. high and another 2.62 in. high. In all cases the bottom plates were heated by electric heaters. The top plates were air-cooled for the water and silicone-oil experiments and water-cooled for the mercury tests. To prevent amalgamation, the copper plates of the mercury container were chromium plated. Surface temperatures were measured by thermocouples embedded in the plates. The test results indicate that the heat-transfer coefficients for all liquids investigated may be determined from the relationship Nu=0.069Ra13Pr0.074 In this equation the Nusselt and Rayleigh numbers are based on the distance between the copper plates. The results of this experiment are in reasonable agreement with the data reported by others who used larger containers and different fluids.

scholarly journals Condensation of Novec 649 refrigerant in pipe minichannels

2018 ◽  
Vol 70 ◽  
pp. 02002 ◽  
Author(s):  
Tadeusz Bohdal ◽  
Henryk Charun ◽  
Małgorzata Sikora
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Mass Flux ◽  
Flow Structures ◽  
Test Results ◽  
Calculation Results ◽  
Vapour Quality ◽  
Inner Diameter

The paper presents the results of experimental investigation of Novec 649 refrigerant condensation in tube minichannels. This is a low-pressure refrigerant. This investigations are basis for flow structures visualization during condensation in pipe minichannels. The local and the average values of pressure drop (Δp/L) and heat transfer coefficient α in the whole range of the changes of vapour quality (x = 1 ÷ 0) were calculated. On the basis of the obtained test results there was illustrated the influence of the vapour quality x, the mass flux density G and the inner diameter of channel d changes on the studied parameters. These results were compared with the calculation results based on the dependencies of other authors.

scholarly journals Experimental study on heat transfer of concrete at high temperatures under hygrothermal environment

2019 ◽  
Vol 275 ◽  
pp. 02020
Author(s):  
Min Tu ◽  
Jun Deng ◽  
Yi Wang
Keyword(s):  
Heat Transfer ◽  
Temperature Increase ◽  
Concrete Structures ◽  
Fire Damage ◽  
Test Results ◽  
Saturation Degree ◽  
Spalling Failure ◽  
Increase Rate ◽  
Hygrothermal Environment ◽  
Damage Simulation

Safety of concrete structures could be threatened under fire exposure, especially for structures under hygrothermal environment. Existing studies have shown that concrete contains large amount of moisture could induce spalling failure and the temperature is a critical parameter for the damage. However, until now, the study for heat transfer of concrete with different saturation degree remains limited. In this paper, the temperature increase of concrete specimens with different saturation degree is experimentally studied. Results show that the temperature increase rate could be affected by the moisture content significantly, especially for the cases under higher temperatures. The test results could be significant for our future fire damage simulation of concrete structures under hygrothermal environment.

Preliminary Testing of Metal-Based Thermal Barrier Coating in a Spark-Ignition Engine

2009 ◽  
Author(s):  
Michael Marr ◽  
James S. Wallace ◽  
Larry Pershin ◽  
Sanjeev Chandra ◽  
Javad Mostaghimi
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Substrate Surface ◽  
Temperature Fluctuations ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Thermal Barrier ◽  
Cylinder Wall ◽  
Test Results ◽  
Barrier Coating

A novel metal-based thermal barrier coating was tested in a spark-ignition engine. The coating was applied to the surface of aluminum plugs and exposed to in-cylinder conditions through ports in the cylinder wall. Temperatures were measured directly behind the coating and within the plug 3 and 11 mm from the surface. In-cylinder pressures were measured and analyzed to identify and quantify knock. Test results suggest the coating does not significantly reduce overall heat transfer, but it does reduce the magnitude of temperature fluctuations at the substrate surface. It was found that heat transfer can be reduced by reducing the surface roughness of the coating. The presence of the coating did not promote knock.

Hybrid Expansion Revisited

2006 ◽  
Vol 129 (3) ◽  
pp. 482-487 ◽  
Author(s):  
Stanley Yokell
Keyword(s):  
Heat Transfer ◽  
Microscopic Examination ◽  
Load Test ◽  
Shear Load ◽  
Test Results

This paper describes new hitherto unused procedures that combine hydraulic and explosive expanding to produce tube-to-tubesheet joints in tubular heat transfer equipment with thick tubesheets. This paper also interprets shear load test results and microscopic examination of polished and sectioned specimens used to validate the adequacy of the method for producing strong, leak tight joints. It concludes that the method is successful.

The Use of Organic Coatings to Promote Dropwise Condensation of Steam

1987 ◽  
Vol 109 (3) ◽  
pp. 768-774 ◽  
Author(s):  
K. M. Holden ◽  
A. S. Wanniarachchi ◽  
P. J. Marto ◽  
D. H. Boone ◽  
J. W. Rose
Keyword(s):  
Heat Transfer ◽  
Atmospheric Pressure ◽  
Polymer Coatings ◽  
Organic Coatings ◽  
Major Constituent ◽  
Dropwise Condensation ◽  
Test Results ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Sustained Performance

Fourteen polymer coatings were evaluated for their ability to promote and sustain dropwise condensation of steam. Nine of the coatings employed a fluoropolymer as a major constituent; four employed hydrocarbons and one a silicone. Each coating was applied to 25-mm-square by approximately 1-mm-thick metal substrates of brass, copper, copper–nickel, and titanium. While exposed to steam at atmospheric pressure, each coating was visually evaluated for its ability to promote dropwise condensation. Observations were also conducted over a period of 22,000 hr. Hardness and adhesion tests were performed on selected specimens. On the basis of sustained performance, six coatings were selected for application to the outside of 19-mm-dia copper tubes in order to perform a heat transfer evaluation. These tubes were mounted horizontally in a separate apparatus through which steam flowed vertically downward. Steam-side heat transfer coefficients were inferred from overall measurements. Test results indicate that the steam-side heat transfer coefficient can be increased by a factor of five to eight through the use of polymer coatings to promote dropwise condensation.

Sign in / Sign up

Export Citation Format

Share Document