Heat Transfer Characteristics of Aviation Kerosene in Vertical Upward High Flux Tubes at Supercritical Pressure

2016 ◽  
Author(s):  
Jingxiang Chen ◽  
Yachao Song ◽  
Guoqiang Xu ◽  
Jie Wen ◽  
Haiwang Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Mass Flux ◽  
Steel Powder ◽  
Outer Wall ◽  
Powder Coating ◽  
Supercritical Pressure ◽  
Smooth Tube ◽  
High Flux ◽  
Flux Tubes

An experimental investigation on heat transfer peculiarity of kerosene flowing in vertical upward high flux tubes at supercritical pressure is presented. Three inner-sintered steel powder coating tubes (high flux tubes) and one smooth tube are tested under the different super-critical pressure and different mass flux of kerosene in the experiment. Results are found that all three high flux tubes perform much better than smooth tube at the same parameters of the tube and same working conditions. It can be obviously deduced that the outer wall temperature is reduced by the disturbance in the flow field of the sintered metal coating at the inner tube-side, while the reduced mass flux can increase the wall temperature on the contrary. Heat transfer coefficient is found 2.5 times as the smooth tube, yet both too large and too small particle diameters of metal powder sintered on the tube surface can deteriorate heat transfer. Density and viscosity, thermal conductivity of kerosene at different temperatures and pressures under supercritical pressure can be evaluated by using the extended corresponding state principle, which shows good consistency with the experimental results.

Heat Transfer Characteristics of Aviation Kerosene Flowing in Enhanced Tubes at Supercritical Pressure

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Dan Huang ◽  
Wei Li ◽  
Jingxiang Chen ◽  
Zhixiao Zhang ◽  
S. A. Sherif
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Metal Powder ◽  
Particle Diameter ◽  
Smooth Tube ◽  
High Flux ◽  
Heat Transfer Characteristics ◽  
Working Pressure ◽  
Flux Tubes ◽  
Transfer Characteristics

Abstract Results of an experimental investigation on heat transfer characteristics of kerosene flowing in vertical upward high-flux tubes at supercritical pressures are presented. Three metal powder-coated tubes (high-flux tubes) and one smooth tube have been tested and compared. The three high-flux tubes all perform much better than the smooth tube at the same parameters of the tube and same working conditions. The observed enhancement in heat transfer is mainly due to the disturbance introduced in the low field by the metal powder coatings and the differences in the thermophysical properties. The heat transfer coefficient in the metal-coated tube (200 mesh) has been found to be 2.5 times that in the smooth tube. Yet, it has been found that both too large and too small of a particle diameter of the metal powder coating on the tube surface could cause the heat transfer to deteriorate. The high-flux tube with a particle diameter of 200 mesh was found to exhibit the best cooling performance. The pressure drop was observed to increase with the increase of the particle diameter. However, the pressure drop was found to be three orders of magnitude smaller than the working pressure in the test section, thus the pressure drop for all practical purposes may be neglected. The density, viscosity, and thermal conductivity of kerosene at different temperatures and supercritical pressures were evaluated using the extended corresponding state principle, which has been proven to show good consistency with the experimental results.

Experimental Study of Heat Transfer to Supercritical Pressure Water Flowing in a 2×2 Rod Bundle

2014 ◽  
Author(s):  
Han Wang ◽  
Qincheng Bi ◽  
Linchuan Wang ◽  
Haicai Lv ◽  
Laurence K. H. Leung
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Pressure Drop ◽  
Wall Temperature ◽  
Mass Flux ◽  
Heat Fluxes ◽  
Outer Diameter ◽  
Square Channel ◽  
Rod Bundle

An experiment has recently been performed at Xi’an Jiaotong University to study the wall temperature and pressure drop at supercritical pressures with upward flow of water inside a 2×2 rod bundle. A fuel-assembly simulator with four heated rods was installed inside a square channel with rounded corner. The outer diameter of each heated rod is 8 mm with an effective heated length of 600 mm. Experimental parameters covered the pressure of 23–28 MPa, mass flux of 350–1000 kg/m2s and heat flux on the rod surface of 200–1000 kW/m2. According to the experimental data, it was found that the circumferential wall temperature distribution of a heated rod is not uniform. The temperature difference between the maximum and the minimum varies with heat flux and/or mass flux. Heat transfer characteristics of supercritical water in bundle were discussed with respect to various heat fluxes. The effect of heat flux on heat transfer in rod bundles is similar with that in tubes or annuli. In addition, flow resistance reflected in the form of pressure loss has also been studied. Experimental results showed that the total pressure drop increases with bulk enthalpy and mass flux. Four heat transfer correlations developed for supercritical pressures water were compared with the present test data. Predictions of Jackson correlation agrees closely with the experimental data.

The study of temperature regimes of a pipe wall under turbulent regime and supercritical pressures

2020 ◽  
Vol 34 (19) ◽  
pp. 2050182
Author(s):  
J. P. Mammadova ◽  
A. P. Abdullaev ◽  
R. M. Rzayev ◽  
R. F. Kelbaliev ◽  
S. H. Mammadova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Physical Properties ◽  
Wall Temperature ◽  
Reynolds Numbers ◽  
Anomalous Behavior ◽  
Supercritical Pressure ◽  
Engineering Practice ◽  
Turbulent Regime ◽  
Low Reynolds Numbers ◽  
Low Reynolds

The flow regimes of liquids encountered in engineering practice are mainly turbulent due to their structure, with which the features of such flows at supercritical pressure are considered in the work and some results are compared with similar ones obtained at low Reynolds numbers. Under these conditions, the physical properties of the fluid change sharply in the parietal layer and, depending on the values of the heat flux density and temperature, the area of sharp changes in physical properties can move along the flow cross section. Depending on the influence of these factors, the nature of the fluid flow can change, which affects the patterns of heat transfer and, accordingly, the nature of the distribution of wall temperature. In particular, conditions were identified for the appearance of a primary and secondary improved heat transfer regime. The possibility of the existence of an anomalous behavior of heat transfer during a turbulent flow of aromatic hydrocarbons was revealed, the nature of the distribution of the wall temperature along the length of the experimental tube is examined, and the influence of changes in the thermophysical properties of the substance on it is analyzed. The experimental data for water and toluene with a deteriorated heat transfer mode deviate from the calculated by [Formula: see text]25%. As is known, the flow regime of fluids in engineering practice is mainly turbulent in structure. Therefore, it is very important to study the characteristics of such flows at supercritical pressure and compare some results with similar results obtained at low Reynolds numbers.

scholarly journals Heat transfer performance of R1234yf for convective boiling in horizontal micro-fin and smooth tubes

2020 ◽  
Vol 207 ◽  
pp. 01009
Author(s):  
Thanh Nhan Phan ◽  
Van Hung Tran ◽  
Nikola Kaloyanov ◽  
Momchil Vassilev
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Mass Flux ◽  
Heat Transfer Performance ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Transfer Performance ◽  
Convective Boiling ◽  
Penalty Factor ◽  
Smooth Tubes

This study analyses the performance of heat transfer process which occurs in the convective boiling of Hydro fluoro Olefin (HFO) refrigerant, R1234yf, in horizontal tube. Heat transfer and pressure drop of R1234yf are analyzed and computed at the same working conditions on the same size of outer diameter of tube do = 9.52 mm with difference of inner surface, one is a smooth surface and microfin for other. The flow pattern maps were built at 5°C saturation temperature with 8.62 kW/m2 of heat flux, it is presented that flow pattern of helix flow occurs at very low mass flux and low quality, while at that condition on smooth tube the flow is still stratified wavy flow. The comparison of heat transfer performance between microfin and smooth tube would be evaluated on enhancement factor E, penalty factor P and efficiency index I. With the mass flux on the range G = 111 -- 333 kg/m2s for 5°C boiling temperature, the results show that, average value of E is 2.18; 1.45 of P and 1.54 of I. One more impressing thing is that, at the quality “x” larger than 0.8, the dryout phenomenon takes place on smooth tubes while microfin tubes do not have this phenomenon.

Comparison of R410A Condensation Heat Transfer Performance on Three Horizontal Tubes

2017 ◽  
Author(s):  
Xu Chen ◽  
Xiaoqiang Hong ◽  
Wei Li ◽  
David J. Kukulka
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Heat Transfer Performance ◽  
Smooth Tube ◽  
High Mass ◽  
Outer Diameter ◽  
Transfer Performance ◽  
Vapor Quality ◽  
Helical Angle

An experimental investigation of R410A condensation outside a horizontal smooth tube, a herringbone tube and a newly developed enhanced surface EHT tube has been conducted. The herringbone tube has a fin root diameter of 11.43 mm, a helical angle of 21.3 °, 48 fins with a fin height of 0.262 mm and an apex angle of 36 °, the EHT tube has an outer diameter of 11.5 mm with special structure, while the smooth tube has an outer diameter of 11.43 mm. Experiments were taken at a constant saturation temperature of 45 °C, a constant inlet vapor quality of 0.8 and a constant outlet vapor quality of 0.1; mass flux ranging from 5 kg/(m2.s) to 250 kg/(m2.s). Those tubes have different heat transfer performance at different mass flux. The EHT tube has the least heat transfer coefficient than the other two tubes at a low mass flux, while at a high mass flux, the enhanced tubes have a better heat transfer performance than the smooth tube. Heat transfer performance combined with pressure drop measurements reveal that the herringbone tube generally has a better heat transfer performance than the EHT tube, pointing out the herringbone is a wise choice for shell side condensation instead of the EHT tube. Characteristic analysis is made to account for various phenomena in this series of experiments.

Numerical Study of the Effects of Different Buoyancy Models on Supercritical Flow and Heat Transfer

2013 ◽  
Author(s):  
X. Y. Xu ◽  
T. Ma ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Enhancement ◽  
Wall Temperature ◽  
Mass Flux ◽  
Wall Heat Flux ◽  
Turbulent Heat ◽  
Transfer Enhancement ◽  
Temperature Prediction ◽  
Flow And Heat Transfer

Due to the dramatic changes in physical properties, the flow and heat transfer in supercritical fluid are significantly affected by buoyancy effects, especially when the ratio of inlet mass flux and wall heat flux is relatively small. In this study, the heat transfer of supercritical water in uniformly heated vertical tube is numerically investigated with different buoyancy models which are based on different calculation methods of the turbulent heat flux. The applicabilities of these buoyancy models are analyzed both in heat transfer enhancement and deterioration conditions. The simulation results show that these buoyancy models make few differences and give good wall temperature prediction in heat transfer enhancement condition when the ratio of inlet mass flux and wall heat flux is very small. With the increase of wall heat flux, the accuracy of wall temperature prediction reduces, and the differences between these buoyancy models become larger. No buoyancy model can currently make accurate wall temperature prediction in deterioration condition in this study.

Condensation Heat Transfer Characteristics on the Outside of Horizontal Smooth, Herringbone and Enhanced Surface 1EHT Tubes

2015 ◽  
Author(s):  
Xiao-peng Zhou ◽  
David J. Kukulka ◽  
Jing Li ◽  
Jian-Jun Sun ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Saturation Temperature ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Thermal Systems ◽  
Low Mass ◽  
Enhanced Surface

Heat transfer enhancement plays an important role in improving energy efficiency and developing high performance thermal systems. Phase-change heat transfer processes take place in thermal systems; typically heat transfer enhanced tubes are used in these systems and they are designed to increase heat transfer coefficients in evaporation and condensation. Enhanced heat transfer tubes are widely used in refrigeration and air-conditioning applications in order to reduce cost and create a smaller footprint of the application. Microfins, roughness and dimples are often incorporated into the inner surface of tubes in order to enhance heat transfer performance. Under many conditions, enhanced surface tubes can recover more energy and provide the opportunity to advance the design of many heat transfer products. Convective condensation heat transfer and pressure loss characteristics were investigated for R410A on the outside of: (i) a smooth tube (outer diameter 12.7 mm); (ii) an external herringbone tube (fin root diameter 12.7 mm); and (iii) the 1EHT tube (outer diameter 12.7 mm) for very low mass fluxes. Data was obtained for values of mass flux ranging from 8 to 50 kg/(m2 s); at a saturation temperature of 318 K; with an inlet quality of 0.8 (±0.05) and an outlet quality of 0.1 (±0.05). In a comparison of heat transfer at a low mass flux, both the 1EHT tube and the herringbone tube did not perform as well as the smooth tube. And it’s difficult to analyze the reason for this strange phenomenon.

Heat Transfer Considerations for Designing FSW Cryogenic Thermal Structures for Aerospace Applications

2008 ◽  
Author(s):  
Michael A. Langerman
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Wall Temperature ◽  
Outer Wall ◽  
Vibration Damping ◽  
Tank Wall ◽  
Transfer Rates ◽  
Friction Stir ◽  
Damping Characteristics ◽  
Cryogenic Tank

Research was conducted to investigate potential structural design configurations for aerospace cryogenic tank wall applications. The primary design considerations included the vibration damping characteristics under various flight loading conditions and the panel wall thermal resistance under different heat loads. The discussion herein is with regards to the thermal issue, specifically the heat transfer rates across two different panel wall designs that have attractive vibration damping characteristics. The heat transfer rates were evaluated analytically and verified with experimental data. One panel is a corrugated, serpentine-layered design fabricated using friction stir welding. The other panel is an “egg-carton” design fabricated using friction stir spot welding. An important thermal consideration for the cryogenic tank wall design is the minimum outer wall temperature attained during ambient storage or prior to launch. Of the two designs considered herein, neither wall provided sufficient thermal resistance to maintain outer wall temperatures above freezing under ambient conditions. One of the wall designs, however, performed somewhat better. It is shown that when configured with an outer layer of thermal plastic coating both designs could maintain an outer wall temperature within design constraints.

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