Modelling and experimental validation for off-design performance of the helical heat exchanger with LMTD correction taken into account

Phu, Nguyen Minh; Trinh, Nguyên Thị Minh

doi:10.1007/s12206-016-0645-0

Cited by 9 publications

(4 citation statements)

References 21 publications

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“…Heat exchangers performance Off-design pressure drop and heat transfer effectiveness in the heat exchangers deviates from the design values in part-load operation and are simulated based on the method presented in [13]. A 𝛽𝛽 parameter is introduced which accounts for the change in the heat transfer coefficient of a heat exchanger [17]. The shift in heat transfer coefficient is calculated according to the change in flow Nusselt number and the fluid conductivity.…”

Section: 32mentioning

confidence: 99%

Development of a simulation tool for design and off-design performance assessment of offshore combined heat and power cycles

Motamed¹,

Nord²

2022

Linköping Electronic Conference Proceedings

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Ambitious targets for reducing carbon dioxide (CO2) emissions are set by Norwegian authorities to address the concerns about global warming. Emission reductions in the offshore heat and power sector can play a role in reaching these targets. Parts of the efforts in industry and academia to reduce offshore emissions are concerned with introducing new design configurations or proposing novel operational strategies for the combined heat and power cycles. Therefore, there is a desire to have a fast and reliable design and assessment tool to be used in the early design stage. Here, a generalized design and performance simulation tool is developed presenting a design point and off-design simulation of the offshore heat and power cycles. It helps the designer provide a fast and accurate thermodynamic assessment of proposed design solutions. The tool has a graphical user interface to facilitate working with the tool with a minimum level of effort and background knowledge from the user. Five part-load control strategies are included in the tool. The tool is verified with available data in the open literature and the results are shown to be in good agreement with the reference data. A combined heat and power cycle is designed and simulated at part-loads as a case study. The cycle includes a gas turbine, a process heat extraction unit, and an organic Rankine bottoming cycle. The simulated performance of the design case in various control strategies is compared showing a 2.5% emission reduction relative to the baseline control strategy.

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Section: 32mentioning

confidence: 99%

Development of a simulation tool for design and off-design performance assessment of offshore combined heat and power cycles

Motamed¹,

Nord²

2022

Linköping Electronic Conference Proceedings

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“…For a two-phase heat exchanger -in this case, the evaporator-equations could still be used by setting C max = ∞, hence CR = 0. It is suggested in [31] that the heat transfer coefficient can be calculated relative to the design value in off-design conditions.…”

Section: Heat Exchangersmentioning

confidence: 99%

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

Motamed

Nord

2021

Energies

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Power cycles on offshore oil and gas installations are expected to operate more at varied load conditions, especially when rapid growth in renewable energies puts them in a load-following operation. Part-load efficiency enhancement is advantageous since heat to power cycles suffer poor efficiency at part loads. The overall purpose of this article is to improve part-load efficiency in offshore combined cycles. Here, the organic Rankine bottoming cycle with a control strategy based on variable geometry turbine technology is studied to boost part-load efficiency. The Variable Area Nozzle turbine is selected to control cycle mass flow rate and pressure ratio independently. The design and performance of the proposed working strategy are assessed by an in-house developed tool. With the suggested solution, the part-load organic Rankine cycle efficiency is kept close to design value outperforming the other control strategies with sliding pressure, partial admission turbine, and throttling valve control operation. The combined cycle efficiency showed a clear improvement compared to the other strategies, resulting in 2.5 kilotons of annual carbon dioxide emission reduction per gas turbine unit. Compactness, autonomous operation, and acceptable technology readiness level for variable area nozzle turbines facilitate their application in offshore oil and gas installations.

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“…Therefore, performance improvement of the exchangers is always paid attention by researchers. It could be helically coiled tube usage for higher heat transfer than straight tube 1 or application of finned tubes to enhance heat and mass transfer in dehumidifying air coils 2 or utilization of high performance tube to enhance boiling and condensing heat transfer in a water chiller 3 , or introduction of roughness elements to discard the viscous sublayer and create a mix of the primary flow and secondary flow in a fluid channel 4,5 . In recent years, triple-fluid heat exchanger (TFHE) has been widely employed due to high heat exchange capacity and reduced pressure loss compared to dual-fluid heat exchangers 6,7 .…”

Section: Introductionmentioning

confidence: 99%

A Compact EES Program to Predict Axial Temperature Distribution in Triple-fluid Heat Exchanger

Minh¹

2020

Sci. Tech. Dev. J.- Eng. Tech.

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In this paper, a simplified mathematical model is presented to predict the axial temperature distribution of fluids in a three-concentric tube heat exchanger. Calculation results are compared with experimental results to confirm accuracy. The objective of the study is to avoid temperature cross which is very likely to be occurred in triple-fluid heat exchangers. Thereby the designer can adjust the design parameters, e.g. geometric parameters of the exchanger, temperatures or fluid flow rates, so that the temperature cross does not occur. The result of calculating a case shows that at the tube length of 21.5 m, the temperature cross occurs between the hot fluid and the intermediate fluid at a certain position. The shorten tube length to 8.5 m yields desirable gain. EES code and calculation procedure in detail are presented in the current study.

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Modelling and experimental validation for off-design performance of the helical heat exchanger with LMTD correction taken into account

Cited by 9 publications

References 21 publications

Development of a simulation tool for design and off-design performance assessment of offshore combined heat and power cycles

Development of a simulation tool for design and off-design performance assessment of offshore combined heat and power cycles

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

A Compact EES Program to Predict Axial Temperature Distribution in Triple-fluid Heat Exchanger

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