Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers

Navarro, Hélio Aparecido; Cabezas‐Gómez, Luben

doi:10.1590/s0104-66322007000400005

Cited by 67 publications

(37 citation statements)

References 10 publications

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“…The calculation method for the rate of heat transfer is based on the Number of Transfer Units (NTU) method, which has been documented by [10] and applied for complex cross flow heat exchangers by [11]. The algorithm in the code ensures satisfactory results and numerical stability.…”

Section: Recuperator (Scr and Icr Only)mentioning

confidence: 99%

A Review of the Turbine Cooling Fraction for Very High Turbine Entry Temperature Helium Gas Turbine Cycles for Generation IV Reactor Power Plants

Gad-Briggs

Pilidis

Nikolaidis

2017

Journal of Nuclear Engineering and Radiation Science

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of The potential for high Turbine Entry Temperatures (TET) turbines for Nuclear Power Plants (NPPs) require improved materials and sophisticated cooling. Cooling is critical to maintaining mechanical integrity of the turbine for temperatures >1000°C. Increasing TET is one of the solutions for improving efficiency after cycle optimum pressure ratios have been achieved but cooling as a percentage of mass flow will have to increase, resulting in cycle efficiency penalties. To limit this effect, it is necessary to know the maximum allowable blade metal temperature to ensure the minimum cooling fraction is used.

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Section: Recuperator (Scr and Icr Only)mentioning

confidence: 99%

A Review of the Turbine Cooling Fraction for Very High Turbine Entry Temperature Helium Gas Turbine Cycles for Generation IV Reactor Power Plants

Gad-Briggs

Pilidis

Nikolaidis

2017

Journal of Nuclear Engineering and Radiation Science

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“…The calculation method for the rate of heat transfer is based on the Number of Transfer Units (NTU) method, which has been documented by [21] and applied for complex cross flow heat exchangers by [22]. The algorithm in the code ensures satisfactory results and numerical stability.…”

Section: Recuperatormentioning

confidence: 99%

Analyses of the Control System Strategies and Methodology for Part Power Control of the Simple and Intercooled Recuperated Brayton Helium Gas Turbine Cycles for Generation IV Nuclear Power Plants

Gad-Briggs

Pilidis

Nikolaidis

2017

Journal of Nuclear Engineering and Radiation Science

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An important requirement for Generation IV Nuclear Power Plant (NPP) design is the control system, which enables part power operability. The choices of control system methods must ensure variation of load without severe drawbacks on cycle performance. The objective of this study is to assess the control of the NPP under part power operations. The cycles of interest are the simple cycle recuperated (SCR) and the intercooled cycle recuperated (ICR). Control strategies are proposed for NPPs but the focus is on the strategies that result in part power operation using the inventory control method. First, results explaining the performance and load limiting factors of the inventory control method are documented; subsequently, the transient part power performances are also documented. The load versus efficiency curves were also derived from varying the load to understand the efficiency penalties. This is carried out using a modeling and performance simulation tool designed for this study. Results show that the ICR takes ∼102% longer than the SCR to reduce the load to 50% in design point (DP) performance conditions for similar valve flows, which correlates with the volumetric increase for the ICR inventory tank. The efficiency penalties are comparable for both cycles at 50% part power, whereby a 22% drop in cycle efficiency was observed and indicates limiting time at very low part power. The analyses intend to aid the development of cycles for Generation IV NPPs specifically gas cooled fast reactors (GFRs) and very high-temperature reactors (VHTRs), where helium is the coolant.

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“…Bir ısı değiştiricisine giren ve çıkan sıcak ve soğuk akımın etkenlikle olan ilişkisi aşağıdaki eşitliklerde verilmiştir [12].…”

Section: Bir Tek ıSı Değiştiricisi Için Hesaplamaunclassified

Static Simulation of Heat Exchanger Circuit of Cumene Production

Kayabaşı¹,

Kolukısa²

2015

A P J Eng Sci

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ÖzetBir ısı değiştiricisi, iki veya daha fazla sıvı arasındaki, katı veya sıvı arasındaki veya katı parçacıklar ve akışkan arasındaki termal iç enerjisini dışarıdan ısı ve iş girişi olmaksızın gerçekleştiren cihazlardır. Isı değiştiricileri kullanım amaçlarına göre değişik konstrüksiyonlarda, kapasitelerde, boyutlarda ve tiplerde olabilmektedirler. Isı geri kazanım amaçlı kullanılan ısı değiştiricileri sanayi kuruluşlarında yatırım maliyetinde önemli bir yer tutmaktadır. Bu nedenle ısı değiştiricisi seçilirken veya ısı değiştiricisi devreleri tasarlanırken oldukça dikkat edilmeli ve ısı geri kazanımının maksimum olması için doğru ısı değiştiricisi veya efektif bir ısı değiştiricisi devresi tasarlanması gerekmektedir. Bu çalışmada, bir kümen üretim tesisinde bulunan ısı değiştiricisi devresinin statik simülasyonu yapılmıştır. Devreye giriş yapan ve devreden çıkış yapan sıcak ve soğuk akışların koordinatları matris denklemleriyle tanımlanarak devre içerisindeki sıcaklık dağılımları ve devre çıkışındaki sıcaklıklar iterasyona başvurulmadan, özel yazılım ve donanımlara başvurmaksızın yüksek bir doğrulukta elde edilmiştir. Simulasyon sonucunda ısı değiştiricisi devresindeki her bir hücreden geçen sıcak akış ve soğuk akışa ait sıcaklıklar işletme şartları ile örtüşecek şekilde tam doğrulukta elde edilmiştir. Ayrıca devre içerisindeki ısı değiştiricilerindeki sıcaklık dağılımları elde edilerek devrenin statik durumunun izlenmesi sağlanmıştır. AbstractA Heat Exchanger is device which realises thermal internal energy between two or more liquid, solid or liquid or solid particles and fluids without heat and occupation input outside. According to usage purposes heat exchangers may be in various constructions, capacity, size and types. Heat exchangers used for intentional heat recovery have an important situation of investment cost in industrial organizations. Therefore it should be considered quite while heat exchanger selected or heat exchanger circuits designed and it is required to designing correct heat exchanger or an effective heat exchanger network. In this study, it is made of static simulation that heat exchanger network which is found in a cumene production plant. By coordinates of hot and cold flows which enters to circuit and goes output from circuit are defined with matrix equations that temperature distributions in network and temperatures output network are obtained in high accuracy without to recourse iteration, specific software and hardware. In consequence of simulation the temperatures belonging to hot and cold flow passed from each cell in the heat exchanger network are obtained to coincide with the operating conditions in intrinsic accuracy. In addition thereby the temperature distribution within the circuit of the heat exchanger are obtained, following static state of circuit is provided.

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Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers

Cited by 67 publications

References 10 publications

A Review of the Turbine Cooling Fraction for Very High Turbine Entry Temperature Helium Gas Turbine Cycles for Generation IV Reactor Power Plants

A Review of the Turbine Cooling Fraction for Very High Turbine Entry Temperature Helium Gas Turbine Cycles for Generation IV Reactor Power Plants

Analyses of the Control System Strategies and Methodology for Part Power Control of the Simple and Intercooled Recuperated Brayton Helium Gas Turbine Cycles for Generation IV Nuclear Power Plants

Static Simulation of Heat Exchanger Circuit of Cumene Production

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