Thermal and hydraulic numerical study for a novel multi tubes in tube helically coiled heat exchangers: Effects of operating/geometric parameters

Elattar, H.F.; Fouda, A.; Nada, S.A.; Refaey, H.A.; Al‐Zahrani, Ahmed

doi:10.1016/j.ijthermalsci.2018.02.020

Cited by 45 publications

(7 citation statements)

References 24 publications

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“…The overall heat transfer coefficient was calculated from the heat transfer and the external area of the inner tube, and the heat transfer was defined as the average value between the heat released by HFC125 and the heat absorbed by the cooling water [12,13] .…”

Section: Data Processingmentioning

confidence: 99%

“…Wu et al [11] conducted an experimental study of pressure drop and heat transfer in a spiral tube heat exchanger using nanofluid, which was not significantly enhanced by the nanofluid. Elattar et al [12] , Fouda et al [13] studied the heat transfer performance of a multi-tube spiral tube heat exchanger under turbulent flow conditions and analyzed the effect of flow parameters and structural parameters on the thermal, hydrodynamic characteristics of the spiral tube heat exchanger. The comparison between the multi-tube spiral tube heat exchanger and the straight tube heat exchanger shows that the multi-tube spiral tube heat exchanger has better thermal performance and the maximum value of the combined thermo-hydraulic performance factor occurs at N = 3.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of the flow parameters on the heat transfer performance of a two-stage spiral casing heat exchanger

Liu

Wang

et al. 2022

TSE

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The study of the performance of high-efficiency heat pump systems has been a hot issue of general interest in the field of heat pump air conditioning. For the designed and developed two-stage casing tandem heat exchanger of heat pump system, the 3D finite volume method and the realizable k-ε model are used to numerically analyze the influence law of inlet fluid temperature and flow velocity on the overall heat transfer coefficient as well as the Nussle number of inner and outer tubes. The results show that decreasing the inlet water temperature or increasing the inlet refrigerant temperature can improve the overall heat transfer performance; Nuin increases with the increase of water and refrigerant flow rates, while Nuout increases with the increase of water flow rate but decreases with the increase of refrigerant flow rate; Nuin and Nuout both increase with the decrease of water temperature or refrigerant temperature increases.

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Section: Data Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the flow parameters on the heat transfer performance of a two-stage spiral casing heat exchanger

Liu

Wang

et al. 2022

TSE

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“…The efficiency of heat exchanger is defined as [15] : (11) Among them, Where: 𝑄𝑄 avg -average heat exchange capacity of heat exchanger, W; 𝑄𝑄 𝑖𝑖 -heat exchange of fluid at pipe side, W; 𝑄𝑄 0 -heat exchange of fluid at shell side, W; 𝑞𝑞 𝑚𝑚 -mass flow, kg/s; 𝜕𝜕 𝑖𝑖,in -pipe side inlet temperature, ℃; 𝜕𝜕 𝑡𝑡,in -inlet temperature at shell side, ℃.…”

Section: Comprehensive Performance Analysis Of Spiral Tube Heat Excha...mentioning

confidence: 99%

Study on heat transfer characteristics of flow heat coupling of horizontal spiral tube heat exchanger

Wang

Lai

Chen

et al. 2021

TSE

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In view of the complex structural characteristics and special operating environment of the horizontal spiral tube heat exchanger of the shaft sealed nuclear main pump, the numerical simulation method of flow heat coupling is used to analyze the influence of the flow and temperature changes of the fluid on the shell side on the flow field and temperature field of the heat exchanger, explore the influence rules of the inlet parameters on the flow and heat transfer characteristics of the fluid in the heat exchanger, and analyze the enhanced heat transfer performance of the heat exchanger by using the relevant heat transfer criteria. The results show that the horizontal spiral tube fluid generates centrifugal force under the influence of curvature, forming a secondary flow which is different from the straight tube flow heat transfer, and the velocity distribution is concave arc, which will enhance the heat transfer efficiency of the heat exchanger; with the increase of shell side velocity, the degree of fluid disturbance and turbulence increases, while the pressure loss does not change significantly, and the heat transfer performance of the heat exchanger increases; under the given structure and size, the heat transfer performance curve of the heat exchanger shows that the increase of shell side flow and Reynolds number has a significant impact on the enhanced heat transfer of the spiral tube. In practical engineering applications, the heat transfer can be strengthened by appropriately increasing the shell side flow of the heat exchanger.

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“…The above parameters also influence the heat transfer rate of tube-in-tube helical coils [8]. The heat transfer behaviour in the laminar and turbulent conditions of tube-in-tube helical coils can be characterized by the local Nusselt number [9]. The heat transfer rates in helical coils are more dependent on the geometrical parameters when compared with straight tubes [10].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Hydrodynamic Flow Characteristics in Helical Coils with Ovality and Wrinkles

Periasamy

Senthilkumar

Venugopal

et al. 2021

SV-JME

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The forming of helical coils using a rolling process results in geometrical irregularities (wrinkles and ovality) that are likely to influence the hydrodynamic behaviour of the flow field inside the coil in applications such as air generators. In this study, the above behaviour was investigated by experimental and numerical analyses considering the heat exchanger used in dry air generators. In experimental analysis, a three-turn copper helical coil with wrinkles and ovality was investigated to estimate the global hydrodynamic characteristics inside the helical coil. The results were compared with that of the ideal geometry of a coil without wrinkles and ovality. The effect of wrinkles was assessed through friction factor, and the corresponding equivalent surface roughness was found to increase by 5.7 times, owing to the presence of wrinkles in the helical coil. Numerical simulation was conducted to determine the pressure distribution, velocity distribution, and secondary flow inside the helical coil; the results were validated with experimental data. A critical portion of the helical coil with multiple wrinkles was considered for numerical simulation to investigate the localized effects of wrinkles on the flow field behaviour. The analysis in the vicinity of wrinkles revealed negative pressure development during flow, which in turn would cause re-circulation and cavitation that are undesirable.

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Thermal and hydraulic numerical study for a novel multi tubes in tube helically coiled heat exchangers: Effects of operating/geometric parameters

Cited by 45 publications

References 24 publications

Numerical analysis of the flow parameters on the heat transfer performance of a two-stage spiral casing heat exchanger

Numerical analysis of the flow parameters on the heat transfer performance of a two-stage spiral casing heat exchanger

Study on heat transfer characteristics of flow heat coupling of horizontal spiral tube heat exchanger

Investigation of Hydrodynamic Flow Characteristics in Helical Coils with Ovality and Wrinkles

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