scholarly journals Conceptual design and performance evaluation of an innovative high temperature ceramic heat exchanger

2021 ◽  
Vol 2116 (1) ◽  
pp. 012096
Author(s):  
S A Zavattoni ◽  
L Cornolti ◽  
E Arrivabeni ◽  
R Puragliesi ◽  
A Ortona ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
High Temperature ◽  
Heat Exchanger ◽  
Lattice Structure ◽  
Process Efficiency ◽  
Water Dissociation ◽  
Multiscale Approach ◽  
Core Element ◽  
1D Model ◽  
And Performance

Abstract The development of an innovative and highly efficient heat exchanger (HE) solution for gas-gas heat recovery is one of the major objectives of the HYDROSOL-beyond project which aims at enhancing the process efficiency for producing H2 from water dissociation with concentrated sunlight. Because of the very high temperature level of the process (up to 1’400°C), an innovative ceramic HE was proposed with an integrated lattice structure, as secondary surface, to maximize the heat transfer. To assist the design of the HE, a multiscale approach was adopted: a 1D model based on global correlations was developed and a 3D computational fluid dynamics model of the secondary surfaces were generated. The former was applied to assess the performance of the entire HE; while, the latter was exploited to study in detail the thermo-fluid dynamics behavior of a HE core element and to provide the global correlations to be integrated into the 1D model. The effect of the number of lattice layers, located into each channel, on the HE effectiveness was evaluated showing that reducing the height of the secondary structure allows to improve the HE effectiveness from 72% up to 94%.

High Temperature Heat Exchangers (HTHX) for Nuclear Applications

2006 ◽  
Author(s):  
James C. Govern ◽  
Cila V. Herman ◽  
Dennis C. Nagle
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Heat Exchanger Design ◽  
Performance Requirements ◽  
Starting Point ◽  
Temperature Heat ◽  
And Performance ◽  
Design Challenges

Many nuclear engineering applications, current and future, require heat exchangers operating at high temperatures. The operating conditions and performance requirements of these heat exchangers present special design challenges. This paper considers these challenges with respect to a simple heat exchanger design manufactured of a novel carbon material. Heat transfer and effectiveness calculations are performed for several parametric studies regarding heat exchanger parameters. These results are used to better understand the design challenges of high temperature heat exchangers as well as provide a starting point for future optimization work on more complex heat exchanger designs.

scholarly journals Design and Performance Analysis of a Supercritical Carbon Dioxide Heat Exchanger

2020 ◽  
Vol 10 (13) ◽  
pp. 4545 ◽  
Author(s):  
Han Seo ◽  
Jae Eun Cha ◽  
Jaemin Kim ◽  
Injin Sah ◽  
Yong-Wan Kim
Keyword(s):  
Power Generation ◽  
High Pressure ◽  
High Temperature ◽  
Heat Exchanger ◽  
Performance Analysis ◽  
Material Selection ◽  
Tube Bundle ◽  
Outlet Temperature ◽  
Tubular Type ◽  
And Performance

This paper presents a preliminary design and performance analysis of a supercritical CO2 (SCO2) heat exchanger for an SCO2 power generation system. The purpose of designing a SCO2 heat exchanger is to provide a high-temperature and high-pressure heat exchange core technology for advanced SCO2 power generation systems. The target outlet temperature and pressure for the SCO2 heat exchanger were 600 °C and 200 bar, respectively. A tubular type with a staggered tube bundle was selected as the SCO2 heat exchanger, and liquefied petroleum gas (LPG) and air were selected as heat sources. The design of the heat exchanger was based on the material selection and available tube specification. Preliminary performance evaluation of the SCO2 heat exchanger was conducted using an in-house code, and three-dimensional flow and thermal stress analysis were performed to verify the tube’s integrity. The simulation results showed that the tubular type heat exchanger can endure high-temperature and high-pressure conditions under an SCO2 environment.

Design Considerations for Compact Ceramic Off-Set Strip Fin High Temperature Heat Exchangers

2005 ◽  
Author(s):  
Sundaresan Subramanian ◽  
Roald Akberov ◽  
Clayton Ray DeLosier ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Temperature ◽  
Heat Exchanger ◽  
Transfer Enhancement ◽  
Heat Exchanger Design ◽  
Temperature Heat ◽  
Overall Performance ◽  
Offset Strip Fin

This paper deals with the development of a three-dimensional numerical model to predict the overall performance of an advanced high temperature heat exchanger design, up to 1000°C, for the production of hydrogen by the sulfur iodine thermo-chemical cycle used in advanced nuclear reactor concepts. The design is an offset strip-fin, hybrid plate compact heat exchanger made from a liquid silicon impregnated carbon composite material. The two working fluids are helium gas and molten salt (Flinak). The offset strip-fin is chosen as a method of heat transfer enhancement due to the boundary layer restart mechanism between the fins that has a direct effect on heat transfer enhancement. The effects of the fin geometry on the flow field and heat transfer are studied in three-dimensions using Computational Fluid Dynamics (CFD) techniques. The pre-processor GAMBIT is used to create a computational mesh, and the CFD software package FLUENT that is based on the finite volume method is used to produce the numerical results. Fin dimensions need to be chosen that optimize heat transfer and minimize pressure drop. Comparison of the overall performance between two fin shapes (rectangular versus curved edges) is performed using analytical calculations (where available) as well as computational fluid dynamics techniques. The analytical calculations predict larger pressure losses than the numerical simulations. The model developed in this paper will be used to investigate the heat exchanger design parameters in order to find an optimal design.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

scholarly journals Laboratory-Scale Processing and Performance Assessment of Ti–Ta High-Temperature Shape Memory Spring Actuators

2021 ◽  
Author(s):  
A. Paulsen ◽  
H. Dumlu ◽  
D. Piorunek ◽  
D. Langenkämper ◽  
J. Frenzel ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Detrimental Effect ◽  
Wire Drawing ◽  
Fast Heating ◽  
Heating And Cooling ◽  
Arc Melting ◽  
Ω Phase ◽  
And Performance

AbstractTi75Ta25 high-temperature shape memory alloys exhibit a number of features which make it difficult to use them as spring actuators. These include the high melting point of Ta (close to 3000 °C), the affinity of Ti to oxygen which leads to the formation of brittle α-case layers and the tendency to precipitate the ω-phase, which suppresses the martensitic transformation. The present work represents a case study which shows how one can overcome these issues and manufacture high quality Ti75Ta25 tensile spring actuators. The work focusses on processing (arc melting, arc welding, wire drawing, surface treatments and actuator spring geometry setting) and on cyclic actuator testing. It is shown how one can minimize the detrimental effect of ω-phase formation and ensure stable high-temperature actuation by fast heating and cooling and by intermediate rejuvenation anneals. The results are discussed on the basis of fundamental Ti–Ta metallurgy and in the light of Ni–Ti spring actuator performance.

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