Improved General Correlation for Heat Transfer During Gas–Liquid Flow in Horizontal Tubes

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Liquid Mixtures ◽  
Mean Absolute Deviation ◽  
Absolute Deviation ◽  
Earth Gravity ◽  
Horizontal Tubes ◽  
New Correlation ◽  
Wide Range ◽  
Data Points ◽  
Gas Liquid Flow

Heat transfer to two-component gas–liquid mixtures is needed in many industries but there is lack of a well-verified predictive method. A correlation is presented for heat transfer during flow of gas–liquid nonboiling mixtures in horizontal tubes. It has been verified with a wide range of data that includes tube diameters of 4.3–57 mm, pressures from 1 to 4.1 bar, temperatures from 12 to 62 °C, gravity <0.1% to 100% earth gravity, liquid Reynolds number from 9 to 1.2 × 105, and ratio of gas and liquid velocities from 0.24 to 9298. The 946 data points from 18 sources are predicted with mean absolute deviation (MAD) of 19.2%. The same data were compared to five other correlations; they had much larger deviations. Therefore, the new correlation is likely to be helpful in more accurate designs.

General Correlation for Heat Transfer During Two-Component Gas-Liquid Flow in Horizontal Pipes

2018 ◽  
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Liquid Mixtures ◽  
Absolute Deviation ◽  
Horizontal Pipes ◽  
Earth Gravity ◽  
Horizontal Tubes ◽  
Wide Range ◽  
Two Component ◽  
Data Points ◽  
Gas Liquid Flow

Heat transfer to two-component gas-liquid mixtures is needed in many industries but there is lack of a well-verified predictive method. A correlation is presented for heat transfer during flow of gas-liquid non-boiling mixtures in horizontal tubes. It has been verified with a wide range of data that includes: tube diameters 4.3 to 57 mm, pressures from 1 to 4.1 bar, temperatures from 12 to 62 °C, gravity < 0.1 % to 100 % earth gravity, liquid Reynolds number from 9 to 1.2E5, and ratio of gas and liquid velocities from 0.24 to 9298. The 946 data points from 18 sources are predicted with mean absolute deviation of 19.2 %. The same data were compared to several other correlations; they had much larger deviations.

General Correlation for Heat Transfer to Gas–Liquid Flow in Vertical Channels

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Liquid Mixtures ◽  
Absolute Deviation ◽  
General Correlation ◽  
New Correlation ◽  
Rectangular Channels ◽  
Wide Range ◽  
Data Points ◽  
Gas Liquid Flow ◽  
Dry Out

Abstract A general correlation is presented for heat transfer during flow of gas–liquid mixtures flowing in vertical channels prior to dry out. It has been verified with a wide range of data that include upward and downward flow in heated and cooled tubes, annuli, and rectangular channels. The data are from 19 studies and include 14 gas–liquid mixtures with a wide range of properties. The parameters include pressure 1–6.9 bar, temperature 16–115 °C, liquid Reynolds number from 2 to 127,231, superficial gas and liquid velocities up to 87 and 13 m/s, respectively, and ratio of superficial gas and liquid velocities 0.03–1630. The 1022 data points are predicted by the new correlation with mean absolute deviation (MAD) of 18.1%. Several other correlations were also compared to the same data and had MAD of 28.6–45.5%.

A Correlation for Heat Transfer to Two-Component Gas-Liquid Flowing in Vertical Channels

2018 ◽  
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Liquid Mixtures ◽  
Mean Absolute Deviation ◽  
Absolute Deviation ◽  
New Correlation ◽  
Rectangular Channels ◽  
Wide Range ◽  
Two Component ◽  
Data Points

A general correlation is presented for heat transfer during flow of gas-liquid mixtures flowing in vertical channels prior to dryout. It has been verified with a wide range of data that include upwards and downwards flow in heated and cooled tubes, annuli, and rectangular channels. The data are from 19 studies and include 14 gas-liquid mixtures with a very wide range of properties. The parameters include pressure 1 to 6.9 bars, temperature 16 to 115 oC, liquid Reynolds number from 2 to 127231, superficial gas and liquid velocities up to 87 and 13 m/s respectively, and ratio of superficial gas and liquid velocities 0.03 to 1630. The 1022 data points are predicted by the new correlation with mean absolute deviation (MAD) of 18.1 %. Several other correlations were also compared to the same data and had much larger deviations.

A Correlation for Heat Transfer to Gas–Solid Suspensions Flowing in Pipes

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Chemical Processing ◽  
Absolute Deviation ◽  
Solids Loading ◽  
New Correlation ◽  
Accurate Design ◽  
Wide Range ◽  
Data Points ◽  
Loading Ratio ◽  
Vertical Up

Abstract Heat transfer to flowing gas–solid mixtures in pipes is required in many applications including chemical processing, pneumatic transport, and nuclear reactors but no well-verified method for predicting heat transfer is available. A new correlation is presented, which has been validated with a wide range of data that includes a variety of particles (minerals, metals) in several gases. Particle diameters range from 13 to 1130 µm, pipe diameters 5.1 to 77 mm, and the solids loading ratio of 0–520. Flow orientations include horizontal, vertical up, and vertical down. The new correlation has a mean absolute deviation (MAD) of 18.9% with 630 data points from 20 studies. The same data were also compared with six published correlations. Their MAD ranged from 35% to 57%. Hence, the new correlation is likely to help in more accurate design.

scholarly journals Prediction of Heat Transfer during Condensation in Non-Circular Channels

Inventions ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 31
Author(s):  
Mirza M. Shah
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Mass Flux ◽  
Entire Range ◽  
Hydraulic Diameter ◽  
The Other ◽  
Mean Absolute Deviation ◽  
Absolute Deviation ◽  
Reduced Pressure ◽  
Data Points

It is desirable to know whether correlations for condensation in round tubes can be used for non-circular channels. To investigate this matter, a number of well-known correlations for mini and macro channels as well as some for flattened channels were compared to a database for condensation in non-circular channels. Data included square, rectangular, triangular, semi-circular, drum, N, and W shaped channels as well as flattened tubes. The data included 15 fluids, hydraulic diameter 0.067 to 1.46 mm, aspect ratio 0.14 to 7, reduced pressure 0.045 to 0.77, and mass flux from 48 to 1000 kgm−2s−1. None of the correlations worked well for flattened tubes. Data for all other shapes were best predicted by the Shah correlation with mean absolute deviation of 20.1% with 1120 data points from 22 sources. None of the other correlations was found satisfactory over the entire range.

A New Heat Transfer Correlation for Supercritical RP-3 Flowing in Vertical Tubes

2017 ◽  
Author(s):  
Longyun Wang ◽  
Zhi Tao ◽  
Jianqin Zhu ◽  
Haiwang Li ◽  
Zeyuan Cheng
Keyword(s):  
Heat Transfer ◽  
Influence Factors ◽  
Hydrocarbon Fuel ◽  
Operating Conditions ◽  
Major Influence ◽  
Absolute Deviation ◽  
New Correlation ◽  
Vertical Tubes ◽  
Correction Terms ◽  
Good Agreement

A new empirical correlation for upward flowing supercritical aviation kerosene RP-3 in the vertical tubes is proposed. In order to obtain the database, numerical simulation with a four-component surrogate model on RP-3 and LS low Reynolds turbulence model in vertical circular tube has been performed. Tubes of diameter 2mm to 10mm are studied and operating conditions cover pressure from 3MPa to 6MPa. Heat flux is 500KW/m2, mass flow rate is 700kg/(m2·s). The numerical results on wall temperature distribution under various conditions are compared with experimental data and a good agreement is achieved. The existing correlations are summarized and classified into three categories. Three representative correlations of each category are selected out to evaluate the applicability in heat transfer of supercritical RP-3. The result shows that correlations concluded from water and carbon-dioxide do not perform well in predicting heat transfer of hydrocarbon fuel. The mean absolute deviation of them is up to 20% and predict about 80% of the entire database within 30% error bands. So a new correlation which is applicable to different working conditions for supercritical RP-3 is put forward. Gnielinski type has been adapted as the basis of the new correlation for its higher accuracy. In consideration of major influence factors of supercritical heat transfer, correction terms of density and buoyancy effect are added in. The new correlation has a MAD of 9.26%, predicting 90.6% of the entire database within ±15% error bands. The comparisons validate the applicability of the new correlation.

Experimental Identification of Steady-State Turbomachinery Heat Transfer Using Nondimensional Groups

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Markus Baumann ◽  
Christian Koch ◽  
Stephan Staudacher
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Gas Turbines ◽  
Experimental Identification ◽  
Wide Range ◽  
Nonsteady State ◽  
Data Points ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Turboshaft Engine

Abstract Diabatic performance modeling is a prerequisite for engine condition monitoring based on nonsteady-state data points (e.g., Putz et al. 2017, “Jet Engine Gas Path Analysis Based on Takeoff Performance Snapshots,” ASME J. Eng. Gas Turbines Power, 139(11), p. 111201.). The importance of diabatic effects increases with decreasing engine size. Steady-state diabatic modeling of turbomachinery components is presented using nondimensional parameters derived from a dimensional analysis. The resulting heat transfer maps are approximated using the analytic solution for a pipe. Experimental identification of the maps requires the measurement of casing and gas path temperatures. This approach is demonstrated successfully using a small turboshaft engine as a test vehicle. A limited amount of measurements was needed to generate a steady-state heat transfer map which is valid for a wide range of operating points.

Heat Transfer to Supercritical Water in Smooth-Bore Tubes

1965 ◽  
Vol 87 (4) ◽  
pp. 477-483 ◽  
Author(s):  
H. S. Swenson ◽  
J. R. Carver ◽  
C. R. Kakarala
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Supercritical Water ◽  
Convection Heat Transfer ◽  
Physical Property ◽  
Transfer Coefficients ◽  
Property Variation ◽  
Wide Range ◽  
Fully Developed Turbulent Flow ◽  
Data Points

Local forced convection heat-transfer coefficients for supercritical water flowing inside smooth-bore tubes were obtained experimentally over a range of pressures (3300 to 6000 psia) and bulk temperatures (167 to 1068 F). Because the thermophysical properties of supercritical fluids change rapidly with temperature in the pseudocritical range, conventional forced convection correlations were unable to fit the data. However, a satisfactory correlation for fully developed turbulent flow was obtained by properly modifying the conventional nondimensional model to account for the physical property variation across the boundary layer. Out of 2951 data points, 95 percent lie within ±15 percent of the correlation. It was also found that the same equation correlated supercritical pressure heat-transfer data of carbon dioxide over a wide range of conditions with good accuracy.

Flow Boiling in Horizontal Tubes: Part 1—Development of a Diabatic Two-Phase Flow Pattern Map

1998 ◽  
Vol 120 (1) ◽  
pp. 140-147 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Parameters ◽  
Horizontal Tubes ◽  
Flow Pattern Map ◽  
Wide Range ◽  
Data Points

An improved two-phase flow pattern map is proposed for evaporation in horizontal tubes. The new map was developed based on flow pattern data for five different refrigerants covering a wide range of mass velocities and vapor qualities. The new map is valid for both adiabatic and diabatic (evaporating) flows and accurately identifies about 96 percent of the 702 data points. In addition, the new flow pattern map includes the prediction of the onset of dryout at the top of the tube during evaporation inside horizontal tubes as a function of heat flux and flow parameters.

Probabilistic Flow-Pattern-Based Heat Transfer for Condensing Intermittent Flow in Smooth Horizontal Tubes

2010 ◽  
Author(s):  
Josua P. Meyer ◽  
Marcel Christians ◽  
Leon Liebenberg ◽  
Eugene van Rooyen
Keyword(s):  
Heat Transfer ◽  
Saturation Temperature ◽  
Prediction Method ◽  
Intermittent Flow ◽  
Absolute Deviation ◽  
Horizontal Tubes ◽  
Mass Fluxes ◽  
Probabilistic Flow ◽  
R 134A ◽  
Main Candidate

A signal analysis method used for condensing refrigerants is presented, which resulted in a modification of the prediction method for heat transfer based on probabilistic time-fractional results. An objective visual method for discrimination of flow patterns and determining probabilistic time-fractions in intermittent flow was developed. The frequency domain was identified as the main candidate for discrimination of sub-regimes present in intermittent flow. Experimental work was conducted using refrigerants R-22 and R-134a, at an average saturation temperature of 40°C, with mass fluxes ranging from 200–700 kg/m2s, and with test section inlet vapour qualities ranging from 0.65 down to 0.10. These test conditions mostly represented intermittent flow. The modified correlation predicted the experimental data with a mean absolute deviation of 10%.

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