Experiments on air bubbles injection into a vertical shell and coiled tube heat exchanger; exergy and NTU analysis

Dizaji, Hamed Sadighi; Jafarmadar, Samad; Abbasalizadeh, Majid

doi:10.1016/j.enconman.2015.07.044

Cited by 70 publications

(11 citation statements)

References 13 publications

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“…Commonly, the accuracy of experimental data depends on the measuring tools and measuring techniques. The uncertainties due to some independent variables were evaluated using the following formula [42]:…”

Section: Uncertainty Analysismentioning

confidence: 99%

Experimental investigation of the thermal performance of a helical coil latent heat thermal energy storage for solar energy applications

Mahdi

Mahood

Khadom

et al. 2019

Thermal Science and Engineering Progress

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Section: Uncertainty Analysismentioning

confidence: 99%

Experimental investigation of the thermal performance of a helical coil latent heat thermal energy storage for solar energy applications

Mahdi

Mahood

Khadom

et al. 2019

Thermal Science and Engineering Progress

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“…The ejection phenomena and the throttling effect of the corrugations lead to more stability of the small pieces of the fouling substances and weaken the effect of gravity on these parcels. On the other hand, the corrugations interrupt the development of the boundary layer and increase the turbulence intensity of the mainstream which leads to the improvement of heat transfer and increases the stability of the parcels within the flow stream [5][6][7]. Furthermore, in recent years, the application of air injection is proposed as a very effective method for heat *Corresponding Author Institutional Email: P.ahmadi@urmia.ac.ir (P. Ahmadi Moghaddam) transfer improvement within thermal systems [8,9].…”

Section: Introductionmentioning

confidence: 99%

Fouling Performance of A Horizontal Corrugated Tube due to Air Injection

2022

IJE

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In the present study, the fouling performance of a circumferentially corrugated tube was probed due to the air injection. The molasses of sugar beet was considered as the working fluid. The tube was considered to be under constant heat flux. Also, the flow rate of the molasses of sugar beet was considered to be constant. Five different flow rates of the airstream were considered to check the effect of airflow rate. The flow rate of working fluid was kept at the constant flow rate of 2 L/min. The tests were conducted for 5000s (84 minutes). For a better understanding of the nature of the flow, the structure of two-phase steam was recorded via a Canon SX540 Camera. The results presented that the air injection in the corrugated tube will completely change the structure of the working fluid which will bring a very turbulent structure for the working fluid. The thermal results presented that during the testing time, the air injection will keep the heat transfer coefficient about 120% higher than a single-phase stream. The mass evaluation results revealed that the air injection could decrease the weight of fouled substance up to 75%.

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“…They stated that the flow rate of the gas phase has a direct effect on cost savings. Dizaji et al., 24 in an experimental investigation, used air bubble injection to intensify the heat transfer rate at a shell and coiled tube heat exchanger. Their findings showed that by using air bubbles injection, a significant increment occurs in the thermal performance of the shell and coiled tube heat exchanger.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on thermal behavior of non-boiling slug and bubbly two phase-flow in helical tube with spiral

Rezazadeh

Jafarmadar

Niaki

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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The present study provides experimental results of the flow pattern and thermal behavior of a none-boiling air-water two-phase flow in a helical tube with a turbulator. In order to evaluate the thermal behavior, a glass tube was put under constant heat flux. The inlet, outlet, and surface temperature of the helical tube were measured to calculate the heat transfer coefficient. The results showed that the addition of the turbulator in the helical tube leads to a rapid conversion from bubble flow to slug flow. Also, the formed bubbles are much smaller and spread radially throughout the pipe. Findings showed that the turbulator significantly improved the heat transfer of the two-phase flow, in which ratios of heat transfer enhancement with and without turbulator is 28% and 19%, respectively. Finally, cost-to-benefit ratio (C.B.R) analysis confirmed that when air-water two-phase flow transits through the helical tube are not affected by the presence or absence of turbulator.

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Experiments on air bubbles injection into a vertical shell and coiled tube heat exchanger; exergy and NTU analysis

Cited by 70 publications

References 13 publications

Experimental investigation of the thermal performance of a helical coil latent heat thermal energy storage for solar energy applications

Experimental investigation of the thermal performance of a helical coil latent heat thermal energy storage for solar energy applications

Fouling Performance of A Horizontal Corrugated Tube due to Air Injection

Experimental investigation on thermal behavior of non-boiling slug and bubbly two phase-flow in helical tube with spiral

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