scholarly journals Determination of rolling forces of corrugated profiles on stainless belt of heat exchanger for wind tunnels

2021 ◽  
Vol 5 (2) ◽  
pp. 106-112
Author(s):  
Yu. V. Shchipkova ◽  
◽  
A. Yu. Popov ◽  
Yu. A. Rogoza ◽  
D. A. Kormakov ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Storage ◽  
Wind Tunnels ◽  
Milling Machine ◽  
Force Measurements ◽  
Regenerative Heat ◽  
Steel Strips ◽  
Effective Form ◽  
Excessive Load

The efficiency of regenerative heat exchangers with heat storage nozzles made of rolled corrugated tapes depends on the type of their corrugation profile. The most effective form is a triangular one with sharp peaks and troughs. It is technically advisable to get corrugations of a given shape by rolling between two rollers. Determining the required contact load and forces is one of the main tasks when rolling corrugated belts. Insufficient load leads to incomplete formation of the profile, and excessive load leads to warping of the belt. The article presents the results of an experimental study aimed at determining the required load when rolling a corrugated heat exchanger belt for wind tunnels. Experiments and force measurements are carried out on a standard milling machine with a spring dynamometer. The results of the experiment are applied to stainless steel strips with a thickness of 0,3 to 0,4 mm and triangular fluting

scholarly journals Determination of static and dynamic forces for manufacture of corrugated belts for wind tunnel heat exchangers

2021 ◽  
Vol 5 (3) ◽  
pp. 91-98
Author(s):  
Yu. V. Shchipkova ◽  
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Heat Exchanger ◽  
Wind Tunnel ◽  
Heat Exchangers ◽  
Wind Tunnels ◽  
Milling Machine ◽  
Machine Model ◽  
Dynamic Forces

The article presents the results of an experimental study aimed at determining the required load when rolling a corrugated heat exchanger belt for wind tunnels. The experiments are carried out on a horizontal milling machine model 6H81. The results of the experiment are applied to stainless steel tapes with a thickness of 0,3 to 0,4 mm.

Roller Profiling for Shaping Corrugated Profiles on the Heat Exchanger Tape for Wind Tunnels

2021 ◽  
pp. 16-27
Author(s):  
Yu.V. Shchipkova ◽  
A.Yu. Popov
Keyword(s):  
Plastic Deformation ◽  
Heat Exchanger ◽  
Contact Pressure ◽  
Heat Exchangers ◽  
Wind Tunnels ◽  
Regenerative Heat ◽  
Elastic Aftereffect ◽  
Study Results ◽  
Profile Correction ◽  
Profiling Techniques

The efficiency of regenerative heat exchangers with heat-accumulating nozzles made of rolled corrugated tapes depends on the profile of their corrugation. It is technologically difficult to obtain corrugations of a given shape by copying --- stamping. It is technically more expedientto form such a profile by rolling between two rollers. The contact area is smaller, and the contact pressure is significantly higher. In this case, the shape and accuracy of the tape profile are determined by the accuracy of calculation and manufacturing of the profile of the rollers. The length of the profiling zone and the contact pressure depend on the diameter of the rollers. To apply the known profiling techniques when calculating the corrugated profile of the rollers, it is necessary to find the position of the centroid. However, the difficulty is in the tape between the rollers whose thickness cannot be neglected. Therefore, the problem is solved by rolling the roller and the rail smooth, where the tape with a profile formed on it is considered as a rail. The paper introduces a technique of roller profiling taking into account the above factors. When profiling the rollers, the springing of the tape, i.e., elastic aftereffect of plastic deformation, is taken into account. The suitable diameter of the rollers has been determined. The study results in a method developed for calculating the rollers corrugation profile, taking into account the established parameters, i.e., diameters of the centroids and rollers, and the rollers teeth profile correction value, depending on the tape springing during rolling

scholarly journals Effect of Twisted Fin Array in a Triple-Tube Latent Heat Storage System during the Charging Mode

2021 ◽  
Vol 13 (5) ◽  
pp. 2685
Author(s):  
Mohammad Ghalambaz ◽  
Jasim M. Mahdi ◽  
Amirhossein Shafaghat ◽  
Amir Hossein Eisapour ◽  
Obai Younis ◽  
...  
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Latent Heat ◽  
Thermal Energy ◽  
Heat Storage ◽  
Hot Water ◽  
Melting Time ◽  
Latent Heat Storage ◽  
Tube Heat Exchanger ◽  
Storage Rate

This study aims to assess the effect of adding twisted fins in a triple-tube heat exchanger used for latent heat storage compared with using straight fins and no fins. In the proposed heat exchanger, phase change material (PCM) is placed between the middle annulus while hot water is passed in the inner tube and outer annulus in a counter-current direction, as a superior method to melt the PCM and store the thermal energy. The behavior of the system was assessed regarding the liquid fraction and temperature distributions as well as charging time and energy storage rate. The results indicate the advantages of adding twisted fins compared with those of using straight fins. The effect of several twisted fins was also studied to discover its effectiveness on the melting rate. The results demonstrate that deployment of four twisted fins reduced the melting time by 18% compared with using the same number of straight fins, and 25% compared with the no-fins case considering a similar PCM mass. Moreover, the melting time for the case of using four straight fins was 8.3% lower than that compared with the no-fins case. By raising the fins’ number from two to four and six, the heat storage rate rose 14.2% and 25.4%, respectively. This study presents the effects of novel configurations of fins in PCM-based thermal energy storage to deliver innovative products toward commercialization, which can be manufactured with additive manufacturing.

scholarly journals Thermal Energy Storage Performance of Tetrabutylammonium Acrylate Hydrate as Phase Change Materials

2021 ◽  
Vol 11 (11) ◽  
pp. 4848
Author(s):  
Hitoshi Kiyokawa ◽  
Hiroki Tokutomi ◽  
Shinichi Ishida ◽  
Hiroaki Nishi ◽  
Ryo Ohmura
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Solid Phase ◽  
Agitation Rate ◽  
Mechanical Agitation ◽  
External Forces

Kinetic characteristics of thermal energy storage (TES) using tetrabutylammonium acrylate (TBAAc) hydrate were experimentally evaluated for practical use as PCMs. Mechanical agitation or ultrasonic vibration was added to detach the hydrate adhesion on the heat exchanger, which could be a thermal resistance. The effect of the external forces also was evaluated by changing their rotation rate and frequency. When the agitation rate was 600 rpm, the system achieved TES density of 140 MJ/m3 in 2.9 hours. This value is comparable to the ideal performance of ice TES when its solid phase fraction is 45%. UA/V (U: thermal transfer coefficient, A: surface area of the heat exchange coil, V: volume of the TES medium) is known as an index of the ease of heat transfer in a heat exchanger. UA/V obtained in this study was comparable to that of other common heat exchangers, which means the equivalent performance would be available by setting the similar UA/V. In this study, we succeeded in obtaining practical data for heat storage by TBAAc hydrate. The data obtained in this study will be a great help for the practical application of hydrate heat storage in the future.

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