scholarly journals Experimental investigation on straight and u-bend double tube heat exchanger with active and passive enhancement methods

2018 ◽  
Vol 240 ◽  
pp. 02001 ◽  
Author(s):  
Rafal Andrzejczyk ◽  
Tomasz Muszynski ◽  
Przemysław Kozak
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Experimental Models ◽  
Transfer Coefficients ◽  
Pressure Drops ◽  
Tube Heat Exchanger ◽  
Heat Transfer Efficiency ◽  
Air Blowing ◽  
Experimental Values ◽  
Water Mass Flow Rate

Authors in this work want to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. In the study, Wilson plot approach was applied in order to estimate heat transfer coefficients for all heat exchanger (HX) configurations. The study focuses on experimental values of heat transfer coefficient (HTC) and pressure drops. The primary objectives of the work are to: I. Provide an experimental comprehensive database for HTC and pressure drops; II. Analysis effect of different flow conditions e.g. water mass flow rate, the void fraction on heat transfer and hydraulic performance of tested elements. III. Compare influences of both passive and active methods at the efficiency of simple heat exchangers constructions; IV. Validation experimental results with selected experimental models from the open literature.

Internal, Shellside Heat Transfer and Pressure Drop Characteristics for a Shell and Tube Heat Exchanger

1985 ◽  
Vol 107 (2) ◽  
pp. 345-353 ◽  
Author(s):  
E. M. Sparrow ◽  
J. A. Perez
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Thermal Loading ◽  
Compartment Pressure ◽  
Transfer Coefficients ◽  
Pressure Drops ◽  
Tube Heat Exchanger ◽  
Heat Transfer Coefficients ◽  
Shell And Tube

Per-tube heat transfer coefficients and per-compartment and intracompartment pressure drops were measured on the shell side of a shell and tube heat exchanger. The main focus of the work was to determine the response of these quantities to variations in the size of the baffle window; the Reynolds number was also varied parametrically. The pressure measurements showed that the fluid flow is fully developed downstream of the first compartment of the heat exchanger and that the per-compartment pressure drop is constant in the fully developed regime. Within a compartment, the pressure drop in the upstream half is much larger than that in the downstream half. The per-tube heat transfer coefficients vary substantially within a given compartment (on the order of a factor of two), giving rise to a nonuniform thermal loading of the tubes. Row-average and compartment-average heat transfer coefficients were also evaluated. The lowest row-average coefficients were those for the first and last rows in a compartment, while the highest coefficient is that for the row just upstream of the baffle edge. It was demonstrated that the per-tube heat transfer coefficients are streamwise periodic for a module consisting of two consecutive compartments.

Simulation of Temperature Field of Soil Inside Drilling around a Vertically Buried Single-U-Tube Ground Heat Exchanger

2011 ◽  
Vol 393-395 ◽  
pp. 943-946
Author(s):  
Zhen Yu Du
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Heat Transfer Efficiency ◽  
Ground Source ◽  
Practical Engineering ◽  
One Year

In this paper, the mathematical physical model of the heat and moisture transfer, which is about a vertical single-U-tube heat exchanger of a ground source heat pump (GSHP), is used to simulate the soil temperature fields inside drilling around a vertical single-U-tube ground source heat exchanger. The soil temperature fields inside drilling in the GSHP project running for one year are computed numerically. It shows that soil structure, cooling and heating load, cooling and heating period, and convalescence period have been determined by practical engineering conditions, the distance in the plane between drillings have a huge influence on heat transfer effect, only when the distance is designed reasonably, can it be possible to make sure normal heat transfer efficiency.

scholarly journals Heat transfer rates in hot shell, cold tube inclined baffled small shell, and tube heat exchanger using CFD and experimental approach

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Devanand D. Chillal ◽  
◽  
Uday C. Kapale ◽  
N.R. Banapurmath ◽  
T. M. Yunus Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Liquid Flow ◽  
Cfd Analysis ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Tube Heat Exchanger ◽  
Heat Transfer Coefficients ◽  
Shell And Tube ◽  
Cold Liquid

The work presented is an effort to realize the changes occurring for convective coefficients of heat transfer in STHX fitted with inclined baffles. Effort has been undertaken using Fluent, a commercially available CFD code ona CAD model of small STHX with inclined baffles with cold liquid flowing into the tubes and hot liquid flowing in the shell. Four sets of CFD analysis have been carried out. The hot liquid flow rate through shell compartments varied from 0.2 kg/sec to 0.8 kg/sec in steps of 0.2 kg/sec, while keeping the cold liquid flow condition in tube at 0.4 kg/sec constant. Heat transfer rates, compartment temperatures, and overall heat transfer coefficients, for cold liquid and hot liquid, were studied. The results given by the software using CFD approach were appreciable and comparatively in agreement with the results available by the experimental work, which was undertaken for the same set of inlet pressure conditions, liquid flow rates, and inlet temperatures of liquid for both hot and cold liquids. The experimental output results were also used to validate the results given by the CFD software. The results from the CFD analysis were further used to conclude the effect of baffle inclination on heat duty. The process thus followed also helped realize the effects of baffle inclination on convective heat transfer coefficient of the liquid flow through the shell in an inclined baffle shell and tube heat exchanger. The temperature plots for both cold and hot liquid were also generated for understanding the compartmental temperature distributions inclusive of the inlet and outlet compartments. The heat duty for a heat exchanger has been found to increase with the increase in baffle inclinations from zero degree to 20 degrees. Likewise, the convective heat transfer coefficients have also been found to increase with the increase in baffle inclinations.

scholarly journals Thermal-Hydraulic Studies on the Shell-and-Tube Heat Exchanger with Minijets

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3276 ◽  
Author(s):  
Jan Wajs ◽  
Michał Bajor ◽  
Dariusz Mikielewicz
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Waste Heat ◽  
Experimental Studies ◽  
Convection Heat Transfer ◽  
Test Facility ◽  
Experimental Investigations ◽  
Transfer Coefficients ◽  
Tube Heat Exchanger ◽  
Shell And Tube

In this paper a patented design of a heat exchanger with minijets, with a cylindrical construction is presented. It is followed by the results of its systematic experimental investigations in the single-phase convection heat transfer mode. Based on these results, validation of selected correlations (coming from the literature) describing the Nusselt number was carried out. An assessment of the heat exchange intensification level in the described heat exchanger was done through the comparison with a shell-and-tube exchanger of a classical design. The thermal-hydraulic characteristics of both units were the subjects of comparison. They were constructed for the identical thermal conditions, i.e., volumetric flow rates of the working media and the media temperatures at the inlets to the heat exchanger. The experimental studies of both heat exchangers were conducted on the same test facility. An increase in the heat transfer coefficients values for the minijets heat exchanger was observed in comparison with the reference one, whereas the generated minijets caused greater hydraulic resistance. Experimentally confirmed intensification of heat transfer on the air side, makes the proposed minijets heat exchanger application more attractive, for the waste heat utilization systems from gas sources.

Heat Transfer Characterization of a Finned-Tube Heat Exchanger (With and Without Condensation)

1990 ◽  
Vol 112 (1) ◽  
pp. 64-70 ◽  
Author(s):  
S. A. Idem ◽  
A. M. Jacobi ◽  
V. W. Goldschmidt
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Factor Versus ◽  
Finned Tube ◽  
Transfer Coefficients ◽  
Number Range ◽  
Tube Heat Exchanger ◽  
Pressure Losses ◽  
Finned Tube Heat Exchanger

The effects upon the performance of an air-to-water copper finned-tube crossflow heat exchanger due to condensation on the outer surface are considered. A four-tube, two-pass heat exchanger was tested over a Reynolds number range (based on hydraulic diameter) from 400 to 1500. The coil was operated both in overall parallel and overall counterflow configurations. Convective heat and mass transfer coefficients are presented as plots of Colburn j-factor versus Reynolds number. Pressure losses are, similarly, presented as plots of the friction factor versus Reynolds number. Enhancement of sensible heat transfer due to the presence of a condensate film is also considered.

Shell-and-Tube Side Heat Transfer Augmentation by the Use of Wall Radiation in a Crossflow Shell-and-Tube Heat Exchanger

1984 ◽  
Vol 106 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Y. Yamada ◽  
M. Akai ◽  
Y. Mori
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Room Temperature ◽  
Heat Transfer Performance ◽  
Transfer Coefficients ◽  
Tube Heat Exchanger ◽  
Heat Transfer Coefficients ◽  
Heat Transfer Augmentation ◽  
Hot Gas ◽  
Shell And Tube

The heat transfer performance of a crossflow shell-and-tube heat exchanger for high-temperature use in which heat transfer is augmented by the use of wall radiation in both shell and tube sides, is studied. Radiation plates are inserted in the shell side, and twisted cross-tapes in the tube side. Overall heat transfer coefficients are measured to be about a maximum 80 percent larger than those without radiation, where the inlet temperatures of the hot gas range up to 800 °C, while those of the cold gas are about room temperature. Analytical results agree well with experimental results, and an approximate calculation procedure is found to be simple and accurate enough for practical use.

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