Temperature Distribution, Heat Flow and Sea Floor Depth Estimation at Mid-Oceanic Ridges using Small-Scale Convection Model at Base

2009 ◽  
Author(s):  
S. Kriplani
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Depth Estimation ◽  
Small Scale ◽  
Sea Floor ◽  
Convection Model

Experimental and Numerical Evaluation of Small-Scale Cryosurgery Using Ultrafine Cryoprobe

2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Numerical Evaluation ◽  
Small Scale ◽  
Outer Diameter ◽  
Cooling Performance ◽  
The Heat Transfer Coefficient

The objective of this work is to experimentally and numerically evaluate small-scale cryosurgery using an ultrafine cryoprobe. The outer diameter (OD) of the cryoprobe was 550 μm. The cooling performance of the cryoprobe was tested with a freezing experiment using hydrogel at 37 °C. As a result of 1 min of cooling, the surface temperature of the cryoprobe reached −35 °C and the radius of the frozen region was 2 mm. To evaluate the temperature distribution, a numerical simulation was conducted. The temperature distribution in the frozen region and the heat transfer coefficient was discussed.

DISCUSSION. ON HEAT-FLOW AND TEMPERATURE-DISTRIBUTION IN THE GAS-ENGINE.

1909 ◽  
Vol 176 (1909) ◽  
pp. 251-276
Author(s):  
B HOPKINSON ◽  
J C INGLIS ◽  
R E B CROMPTON ◽  
W W BEAUMONT ◽  
E J DAVIS ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Gas Engine

Evaluation of the Rotor Temperature Distribution of an Automotive Turbocharger Under Hot Gas Conditions Including Indirect Experimental Validation

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Christopher Zeh ◽  
Ole Willers ◽  
Thomas Hagemann ◽  
Hubert Schwarze ◽  
Jörg Seume
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Internal Combustion Engines ◽  
Fluid Film ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Hot Gas ◽  
Experimental Identification ◽  
Fluid Film Bearings ◽  
Validation Parameters

Abstract While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFD-model with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modeled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600 °C and the lubricant is supplied at a pressure of 300 kPa with 90 °C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

CORRESPONDENCE. ON HEAT-FLOW AND TEMPERATURE-DISTRIBUTION IN THE GAS ENGINE.

1909 ◽  
Vol 176 (1909) ◽  
pp. 276-286
Author(s):  
R H FERNALD ◽  
H R RICARDO ◽  
R ROYDS ◽  
C H WINGFIELD ◽  
B HOPKINSON
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Gas Engine

Evaluation of the Rotor Temperature Distribution of an Automotive Turbocharger Under Hot Gas Conditions Including Indirect Experimental Validation

2020 ◽  
Author(s):  
Christopher Zeh ◽  
Ole Willers ◽  
Thomas Hagemann ◽  
Hubert Schwarze ◽  
Joerg R. Seume
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Internal Combustion Engines ◽  
Fluid Film ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Hot Gas ◽  
Experimental Identification ◽  
Fluid Film Bearings ◽  
Validation Parameters

Abstract While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFD-model with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modelled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600°C and the lubricant is supplied at a pressure of 300 kPa with 90°C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

Analysis of Oil Film Thickness on a Piston Ring of Diesel Engine: Effect of Oil Film Temperature

2001 ◽  
Author(s):  
Yasuo Harigaya ◽  
Michiyoshi Suzuki ◽  
Masaaki Takiguchi
Keyword(s):  
Diesel Engine ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Film Thickness ◽  
Piston Ring ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Two Dimensional ◽  
Oil Film ◽  
The Mean

Abstract This paper describes that an analysis of oil film thickness on a piston ring of diesel engine. The oil film thickness has been performed by using Reynolds equation and unsteady, two-dimensional (2-D) energy equation with a heat generated from viscous dissipation. The temperature distribution in the oil film is calculated by using the energy equation and the mean oil film temperature is computed. Then the viscosity of oil film is estimated by using the mean oil film temperature. The effect of oil film temperature on the oil film thickness of a piston ring was examined. This model has been verified with published experimental results. Moreover, the heat flow at ring and liner surfaces was examined. As a result, the oil film thickness could be calculated by using the viscosity estimated from the mean oil film temperature and the calculated value is agreement with the measured values.

Experimental and Numerical Evaluation of Small-Scale Cryosurgery Using Ultrafine Cryoprobe

2013 ◽  
Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Biological Tissue ◽  
Bioheat Transfer ◽  
Small Scale ◽  
Outer Diameter ◽  
Two Phase ◽  
Inner Diameter ◽  
Surgical Treatments ◽  
Tube Structure

Cryosurgery is one of the surgical treatments using a frozen phenomenon in biological tissue. In order to reduce the invasiveness of cryosurgery, the miniaturization of cryoprobe, which is a cooling device for cryosurgery, has been required. The authors have developed a ultrafine cryoprobe for realizing low-invasive cryosurgery by the local freezing. The objective of this study is to evaluate the small-scale cryosurgery using the ultrafine cryoprobe experimentally and numerically. The ultrafine cryoprobe has a double-tube structure and consists of two stainless microtube. The outer diameter of ultrafine cryoprobe was 550 μm. The inner tube, which has 70 μm in inner diameter, depressurizes the high-pressure liquidized refrigerant. Depressurized refrigerant changes its state to two-phase and passes through the gap between outer and inner tube. The alternative Freon of HFC-23 was used as a refrigerant, which has the boiling point of −82°C at 0.1 MPa. The cooling performance of this ultrafine cryoprobe was tested by the freezing experiment of the gelated water kept at 37°C. The gelated water at 37°C is a substitute of the biological tissue. As a result of the cooling in 1 minute, the surface temperature of the ultrafine cryoprobe was reached at −35°C and the radius of frozen region was 2 mm. In order to evaluate the temperature distribution in the frozen region, the numerical simulation was conducted. The two-dimensional axisymmetric bioheat transfer equation with phase change was solved. By using the result from the numerical simulation, the temperature distribution in the frozen region and expected necrosis area is discussed.

Auriferous chert, banded iron formation, and related volcanogenic hydrothermal alteration, Atik Lake, Manitoba

1989 ◽  
Vol 26 (12) ◽  
pp. 2676-2690 ◽  
Author(s):  
Louis R. Bernier ◽  
Wallace H. MacLean
Keyword(s):  
Hydrothermal Alteration ◽  
Earth Element ◽  
Massive Sulfide ◽  
Iron Formation ◽  
Small Scale ◽  
Banded Iron Formation ◽  
Sulfide Deposits ◽  
Sea Floor ◽  
Facies Metamorphism ◽  
Altered Basalt

Small-scale alteration pipes and stratiform alteration in Archean glomeroporphyritic tholeiitic basalts at Atik Lake, Manitoba, stratigraphically underlie silicate-oxide banded iron formation (BIF) and auriferous sulfide-bearing chert. The auriferous chert is locally interbedded with graphitic argillite, indicating euxinic conditions during deposition. Cordierite–gedrite rocks formed by recrystallization of alteration assemblages during the lower amphibolite-facies metamorphism (T = 550 °C, P = 2.5 kbar). Al2O3, TiO2, Zr, and Nb, which were relatively immobile during alteration, have been used to monitor igneous differentiation and alteration. Volcanogenic hydrothermal alteration resulted in depletion of Ca, Si, Mg, Na, and Sr in the altered basalt and the addition of K, Fe, Rb, and Ba. This was accompanied by mass and volume losses of up to 25%. The mineralizing fluid was reducing and somewhat acidic. Rare-earth-element (REE) profiles of BIF and graphitic argillite, normalized to Archean shale, are less steep ((La/Lu)N = 0.51 and 0.49 respectively), than those of both mineralized chert ((La/Lu)N = 0.04) and recent sea-floor, siliceous, gold-enriched massive sulfides ((La/Lu)N = 0.11). REE profiles and Boström's plot suggest that the auriferous, sulfide-bearing chert formed by mixing of hydrothermal and detrital components. The overall chemical changes in the Atik Lake alteration system are comparable to those in Noranda-type massive-sulfide deposits. The trace-metal association in the auriferous chert is similar to that at some modern sea-floor hydrothermal sites.

Observations of the ABL Structures over a Heterogeneous Land Surface during IHOP_2002

2007 ◽  
Vol 8 (2) ◽  
pp. 221-244 ◽  
Author(s):  
Song-Lak Kang ◽  
Kenneth J. Davis ◽  
Margaret LeMone
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Land Surface ◽  
Joint Probability ◽  
Surface Flux ◽  
Weather Conditions ◽  
Surface Heterogeneity ◽  
Small Scale ◽  
Mesoscale Circulations ◽  
Obukhov Length

Abstract This study analyzes data collected by aircraft and surface flux sites over a 60-km north–south-oriented aircraft track for five fair-weather days during the International H2O Project (IHOP_2002) to investigate the atmospheric boundary layer (ABL) structures over a heterogeneous land surface under different background weather conditions. The surface skin temperature distribution over the aircraft track in this case is mostly explained by the soil thermal properties and soil moisture, and corresponds to the observed ABL depths except one day having a weak surface temperature gradient and a weak capping inversion. For the other four days, the blending height of the surface heterogeneity likely exceeds the ABL depth and thus the ABL establishes equilibrium with local surface conditions. Among the four days, two days having relatively small Obukhov lengths are evaluated to show the background weather conditions under which small-scale surface heterogeneity can influence the entire ABL. In fact, on one of these two days, relatively small-scale features of the surface temperature distribution can be seen in the ABL depth distribution. On the two small Obukhov length days multiresolution spectra and joint probability distributions, which are applied to the data collected from repeated low-level aircraft passes, both imply the existence of surface-heterogeneity-generated mesoscale circulations on scales of 10 km or more. Also on these two small Obukhov length days, the vertical profiles of dimensionless variances of velocity, temperature, and moisture show large deviations from the similarity curves, which also imply the existence of mesoscale circulations.

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