The Periodic Method for Testing Compact Heat Exchanger Surfaces

1974 ◽  
Vol 96 (2) ◽  
pp. 87-94 ◽  
Author(s):  
J. H. Stang ◽  
J. E. Bush
Keyword(s):  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Limited Attention ◽  
Compact Heat Exchanger ◽  
Transfer Performance ◽  
Test Results ◽  
The Past ◽  
Temperature Waves ◽  
State Technique ◽  
Periodic Method

The regular periodic method for testing the heat transfer performance of heat exchanger cores is studied in detail. This method, which has received very limited attention in the past, has certain advantages over the more conventional steady-state technique. It is shown to be useful especially in testing matrix surfaces. A theoretical analysis is performed, forming the basis for the periodic method. Directions for use in the range 0.2 < Ntu < 50, an uncertainty analysis, and test results for 2.6 < Ntu < 36.6 are included. It is concluded that the periodic method has the major advantages of: a wide Ntu range, easily generated experimental temperature waves, and the accuracy of an integral technique.

Heat Transfer of Aluminium-Oxide Nanofluids in a Compact Heat Exchanger

2013 ◽  
Vol 465-466 ◽  
pp. 622-628
Author(s):  
Faiza Mohamed Nasir ◽  
Mohd. H. Bahari ◽  
Y. Aiman
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Superior Performance ◽  
Compact Heat Exchanger ◽  
Transfer Performance ◽  
Test Rig ◽  
Custom Made ◽  
Experimental Works ◽  
Set Up

Experimental works were conducted to investigate the effect of Al2O3 sizes and volumeconcentration on the rate of nanofluids heat transfer in a compact heat exchanger. Two sizes ofAl2O3 nanoparticle, 40 nm and 100 nm, were mixed with demineralized water at 2% and 10%volume concentrations. Sodium Lauryl Sulphate (SLS) powder was added to enhance the mixingprocess and stabilize the dispersion of the nanofluids. A custom-made closed loop test rig weredesigned, fabricated and tested for these experiments. The test rig was set-up to represent the actualapplication of the nanofluids in cooling of a compact heat exchanger. Experimental runs wereconducted which include the runs for water, 40 nm Al2O3-water and 100 nm Al2O3-water. Theresults indicate that Al2O3-water gave better heat transfer performance than water alone. Nanofluidswith 40 nm- Al2O3 gives better heat transfer performance as compared to 100 nm- Al2O3 nanofluids.The results of the current work generally indicate that nanofluids have the potential to enhance theheat transfer of a compact heat exchanger if properly designed. This superior performance of thenanofluids would only be produced if smaller diameter of nanoparticles were used (less than 100nm). No enhancement in heat transfer can be observed by using nanofluids with particle size of 100nm or at higher volume loading (more than 5%).

Experimental Investigation on the Flow and Heat Transfer of an Air-Air Primary Surface Heat Exchanger

2018 ◽  
Author(s):  
Wei Dong ◽  
Shengbao Zhang ◽  
Zhiqiang Guo ◽  
Xiao Yu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Surface Heat ◽  
Transfer Performance ◽  
Test Results ◽  
Flow And Heat Transfer ◽  
The Cross ◽  
Surface Heat Exchanger

The primary surface heat exchanger (PSHE) is a kind of small size, light weight, high integration heat exchanger. The characteristics of the complex internal structure, complex flow pattern and the flow interaction have a great influence on the heat transfer of the air-air primary surface heat exchanger. Five cross-corrugated air-air primary surface heat exchangers with different core configurations are designed and fabricated applying additive manufacturing technology. The cross angle θ of upper and lower corrugated plates is 0°, 15°, 30°, 45°, respectively. An experimental investigation on the flow and heat transfer performance is carried out. The comparison of test results of overall heat transfer coefficient and the pressure drop for different primary heat exchangers is presented. The test results show that the pressure drop is significantly increased with the cross angle increasing, and the heat transfer performance does not show the linear increasing with the cross angle increasing.

The Single-Blow Transient Testing Technique for Compact Heat Exchanger Surfaces

1967 ◽  
Vol 89 (1) ◽  
pp. 29-38 ◽  
Author(s):  
P. F. Pucci ◽  
C. P. Howard ◽  
C. H. Piersall
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Compact Heat Exchanger ◽  
Experimental Facility ◽  
Nickel Plate ◽  
Heat Transfer Characteristics ◽  
Power Penalty ◽  
Testing Technique ◽  
Flow Friction

The single-blow, transient testing technique for determining the heat transfer characteristics of heat exchanger surfaces, with a summary of the underlying theory, a description of an experimental facility, and comments on the applicability of the technique, are presented. Heat transfer and flow friction data are presented for plate-fin type surfaces fabricated of perforated nickel plate. The data indicate that perforations increase heat transfer performance without a large frictional power penalty.

Heat Transfer Performance of Different Nanofluids Flows in a Helically Coiled Heat Exchanger

2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Transfer Performance

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.

scholarly journals Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

2021 ◽  
Vol 11 (19) ◽  
pp. 9261
Author(s):  
Yun-Seok Choi ◽  
Youn-Jea Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Magnetic Fields ◽  
Heat Transfer Performance ◽  
Permanent Magnets ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Improve Heat Transfer ◽  
Fin Tube

As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

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