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.

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 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.

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.

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.

A Modified Correlation for Flow Boiling Heat Transfer in Plate Heat Exchangers

2019 ◽  
Author(s):  
Tong Lv ◽  
Boren Zheng ◽  
Wei Li ◽  
Zahid Ayub
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Plate Heat ◽  
Error Band ◽  
Flow Boiling Heat Transfer ◽  
Compact Size ◽  
Wide Range ◽  
Data Points

Abstract Corrugated plate heat exchangers are increasingly used in two-phase flow applications for their flexible and compact size and the efficient heat transfer performance. This paper presents a review of recent studies on the subject and creates a database containing 533 data points from experiment studies. The collected database covers seven working fluids, a wide range of vapor quality (both mean and local) 0.01–0.94, heat flux 0.5–46 kW m−2, mass flux 5.5–137 kg m−2 s−1, chevron angle 30°–70°, and hydraulic diameter 1.7–4.0 mm. Based on the database a brief comparison between several previous correlations are discussed. A new prediction method for flow boiling heat transfer coefficient is generated by multiple regression analysis and modifying an existing correlation. It was observed that the modified correlation shows a better agreement and predicts 74.3% of data points within ±30% error band and 94.9% within ±50% error band.

A New Correlation of Pool-Boiling Data Including the Effect of Heating Surface Characteristics

1969 ◽  
Vol 91 (2) ◽  
pp. 245-250 ◽  
Author(s):  
B. B. Mikic ◽  
W. M. Rohsenow
Keyword(s):  
Heat Transfer ◽  
Heating Surface ◽  
Surface Characteristics ◽  
Nucleate Boiling ◽  
Surface Characteristic ◽  
Organic Liquids ◽  
Cavity Size ◽  
New Correlation ◽  
Wall Superheat ◽  
Wide Range

The standard approach which relates heat transfer in nucleate boiling to heat transfer to the superheated layer averaged over the time between two successive departures of a bubble from a given site is extended in order to relate the heat flux to the wall superheat through the heating surface characteristic. It was found that the q/A versus ΔT relation depends on the cavity size distribution over the surface. For a known distribution of cavity size, the q/A versus ΔT relation may be predicted, or for unknown characteristics of the boiling surface it is sufficient to have boiling data at one pressure in order to predict the q/A versus ΔT relation of other pressure levels for the same surface and the same liquid. The latter was tried on a wide range of experimental data including water and three organic liquids with good results.

scholarly journals A new heat transfer correlation for oscillating fluid flow

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2459-2466 ◽  
Author(s):  
Mehmet Pamuk
Keyword(s):  
Heat Transfer ◽  
Good Representation ◽  
Flow Conditions ◽  
Heat Transfer Correlation ◽  
New Correlation ◽  
Flow Displacement ◽  
Wide Range ◽  
Study Heat Transfer ◽  
Flow Medium ◽  
Pipe Heat

In this study, heat transfer under oscillating flow conditions has been investigated conducting a wide range of experiments using water as the flow medium. Experimental data have been reduced to obtain relevant heat transfer parameters, namely Nusselt number, and compared to those obtained by the previous researchers. The new correlation obtained herein covers a wide range of flow conditions and it takes into account the effect of Prandtl number which is very sensitive to temperature variations. It is believed to be a good representation of the physical problem. A total of 27 sets of heat transfer experiments, each representing a different frequency, flow displacement length and heat input, have been conducted. Heat applied is absorbed by concentric-pipe heat exchanger where calculations have been performed.

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