scholarly journals Results of the experimental research of the heat-transfer jet pressure to the rock surface during thermal reaming of the borehole

2018 ◽  
Vol 60 ◽  
pp. 00024 ◽  
Author(s):  
Oleksii Voloshyn ◽  
Iryna Potapchuk ◽  
Oleksandr Zhevzhyk ◽  
Mykola Zhovtonoha
Keyword(s):  
Heat Transfer ◽  
Experimental Research ◽  
Lateral Surface ◽  
High Speed ◽  
Rock Surface ◽  
Heat Transfer Medium ◽  
Thermal Methods ◽  
Capacity Coefficient ◽  
Heating Capacity ◽  
Number Of Publications

The performed analysis of scientific sources confirms the existence of a small number of publications devoted to the experimental research of the gasdynamics and plasmodynamics of jets used as a heat-transfer medium in the thermal methods of mine rocks destruction. There are almost no experimental and theoretical publications related to the multiple-jet plasmotrons research. The expediency of own experimental researches performing has been substantiated concerning the lateral inflow of heat-transfer medium high-speed jets on the borehole surface. An experimental research has been made of the interaction between the heat-transfer medium high-speed jets and the surface of the borehole imitated by the through duct. The further prospects of this work are the following: to determine the gas velocity along the lateral surface of the through duct and the value of the heating capacity coefficient from the heat-transfer medium to the lateral surface of the through duct, which imitates the rock surface in the borehole. These parameters are required for creating a mathematical model of the brittle destruction of rocks.

scholarly journals Experimental research on heat transfer in a coupled heat exchanger

2013 ◽  
Vol 17 (5) ◽  
pp. 1437-1441
Author(s):  
Yin Liu ◽  
Jing Ma ◽  
Guang-Hui Zhou ◽  
Ren-Bo Guan
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Experimental Research ◽  
Heating Efficiency ◽  
Air Source Heat Pump ◽  
Heating Capacity ◽  
Different Temperatures ◽  
Double Pipe ◽  
Pipe Heat

The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more than 35%, and the average heating efficiency increases more than 55%, compared with the ordinary air-source heat pump.

Hydronic Coil Performance Evaluation With Nanofluids and Conventional Heat Transfer Fluids

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Roy Strandberg ◽  
Debendra K. Das
Keyword(s):  
Heat Transfer ◽  
Base Fluid ◽  
Finned Tube ◽  
Heat Transfer Fluid ◽  
Al2o3 Nanoparticles ◽  
Heat Transfer Medium ◽  
Heating Coil ◽  
Heat Transfer Fluids ◽  
Heating Capacity ◽  
Coil Performance

The performance of hydronic heating coils with nanoparticle enhanced heat transfer fluids (nanofluids) is evaluated and compared with their performance with a conventional heat transfer fluid comprised of 60% ethylene glycol (EG) and 40% water, by mass (60% EG). The nanofluids analyzed are comprised of either CuO or Al2O3 nanoparticles dispersed in the 60% EG solution. The heating coil has a finned tube configuration commonly used in commercial air handling and ventilating systems. Coil performance is modeled using methods that have been previously developed and validated. The methods are modified by incorporating Nusselt number correlations for nanofluids that have been previously documented in the literature. Similarly, correlations for nanoparticle thermophysical properties that have been documented in the literature are employed. The analyses show that heating coil performance may be enhanced considerably by employing these nanofluid solutions as a heat transfer medium. The model predicts a 16.6% increase in coil heating capacity under certain conditions with the 4% Al2O3/60% EG nanofluid, and a 7.4% increase with the 2% CuO/60% EG nanofluid compared with heating capacity with the base fluid. The model predicts that, for a coil with the Al2O3/60% EG nanofluid, liquid pumping power at a given heating output is reduced when compared with a coil with the base fluid.

An Investigation of Heat Dissipation in High Speed Machining

2009 ◽  
Vol 69-70 ◽  
pp. 480-484 ◽  
Author(s):  
Yan Ming Quan ◽  
Joseph A. Arsecularatne ◽  
Liang Chi Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Integrity ◽  
Temperature Rise ◽  
Material Removal ◽  
High Speed ◽  
Heat Dissipation ◽  
High Speed Machining ◽  
Heat Transfer Medium ◽  
Quantitative Understanding ◽  
Bar Turning

High speed machining (HSM) is finding wider applications due to its economic advantages, such as faster material removal rates, and its technological merits, such as improved surface finish. Nevertheless, the application of HSM also brings about some undesirable results. For example, the tool life and surface integrity of a machined component are greatly affected by the large amount of heat generated, but heat dissipation during an HSM has not been well understood. This paper aims to achieve a quantitative understanding of the heat dissipation in HSM using a bar turning configuration. Based on the calorimetric method and utilizing water as the heat transfer medium, the temperature rise in water was measured to determine the fractions of heat dissipated into the chips, the tool and the workpiece during machining. The obtained results show that the chips take the largest portion of the heat generated and this fraction increases with the increase in feed.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

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