Experimental Study on Peeling Properties of T Type Brazing Joint

2019 ◽  
Vol 795 ◽  
pp. 116-122
Author(s):  
Peng Yang Duan ◽  
Dong Xing Wang ◽  
Guo Yan Zhou ◽  
Shan Tung Tu
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Base Material ◽  
Peel Test ◽  
Type Specimen ◽  
Peel Strength ◽  
Manufacturing Cost ◽  
Standard Samples ◽  
Compact Structure

As the key component of the high temperature gas cooled reactor (HTGR), the performance of the plate fin heat exchanger determines the working efficiency and life of the HTGR. Although the plate-fin structure has lots of advantages such as high efficiency, compact structure, low manufacturing cost, its application will be affected by the vacuum brazing technology and harsh conditions, like high temperature and high pressure. In the practical application of plate-fin heat exchanger, the process of "splitting" between the fin and the diaphragm is very similar to that of the adhesive joint and the delamination of the composite. In the present study, a T-type specimen was designed for the the peel testing of brazed joints. Five kinds of specimens were designed based on the difference between the weld gap and the thickness of the sample base material. The tests were carried out under 450°C and 650°C at five kinds of loading rates, respectively. The peel force-displacement curves of standard samples were obtained . The maximum peel strength and average peel strength were calculated. In addition, the influence of base metal thickness, brazing gap, loading rate and test temperature on the maximum peel strength were analyzed by controlling variable method. Keywords: brazing joint; T-type peel test

Numerical simulation of flow distribution in the header of plate-fin heat exchanger

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040111
Author(s):  
Shu-Ling Tian ◽  
Ying-Ying Shen ◽  
Yao Li ◽  
Hai-Bo Wang ◽  
Sheryar Muhammad ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
High Efficiency ◽  
Flow Distribution ◽  
Optimal Number ◽  
Compact Structure ◽  
Flow Maldistribution

Plate-fin heat exchangers are widely used in industry at present due to their compact structure and high efficiency. However, there is a problem of flow maldistribution, resulting in poor performance of heat exchangers. The influence of the header configuration on fluid flow distribution is studied by using CFD software FLUENT. The numerical results show that the fluid flow inside the header is seriously uneven. The reliability of the numerical simulation is validated against the published results. They are found to be basically consistent within considerable error. The optimal number of the punch baffle is investigated. Various header configuration with different opening ratios have been studied under the same boundary conditions. The gross flow maldistribution parameter (S) is used to evaluate flow nonuniformity, and the flow maldistribution parameters of different schemes under different Reynolds numbers are listed and compared. The optimal header with minimum flow maldistribution parameter is obtained through the performance analysis of headers. It is found that the flow maldistribution of the improved header is significantly smaller compared with the conventional header. Hence, the efficiency of the heat exchanger is effectively enhanced. The conclusion provides a reference for the optimization design of plate-fin heat exchanger.

scholarly journals Analysis of a Fluidized-Bed Particle/Supercritical-CO2 Heat Exchanger in a Concentrating Solar Power System

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Zhiwen Ma ◽  
Janna Martinek
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
High Efficiency ◽  
Solar Power ◽  
Concentrating Solar Power ◽  
Power Cycle ◽  
Temperature Heat ◽  
The Cost

Abstract Concentrating solar power (CSP) development has focused on increasing the energy conversion efficiency and lowering the capital cost. To improve performance, CSP research is moving to high-temperature and high-efficiency designs. One technology approach is to use inexpensive, high-temperature heat transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (sCO2) Brayton power cycle. The sCO2 Brayton power cycle has strong potential to achieve performance targets of 50% thermal-to-electric efficiency and dry cooling at an ambient temperature of up to 40 °C and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat transfer or storage medium that is inexpensive and stable at high temperatures above 1000 °C. The particle/sCO2 heat exchanger (HX) provides a connection between the particles and sCO2 fluid in emerging sCO2 power cycles. This article presents heat transfer modeling to analyze the particle/sCO2 HX design and assess design tradeoffs including the HX cost. The heat transfer process was modeled based on a particle/sCO2 counterflow configuration, and empirical heat transfer correlations for the fluidized bed and sCO2 were used to calculate heat transfer area and estimate the HX cost. A computational fluid dynamics simulation was applied to characterize particle distribution and fluidization. This article shows a path to achieve the cost and performance objectives for a particle/sCO2 HX design by using fluidized-bed technology.

An Optimization Design of the Efficient Tubular Heat Exchanger Structure

2012 ◽  
Vol 197 ◽  
pp. 83-88
Author(s):  
Yong Hong Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Structural Optimization ◽  
Heat Loss ◽  
Optimization Design ◽  
High Efficiency ◽  
Heat Transfer Area ◽  
Compact Structure ◽  
Tubular Heat Exchanger ◽  
Automatic Adjustment

A structural optimization and efficient tubular heat exchanger was designed. Compared with the ordinary heat exchanger on aspects of heat transfer area, heat loss and the structure, this kind of heat exchanger has the advantages of compact structure, high efficiency, low emissions as well as the function of temperature automatic adjustment, so it is of great promotional value.

Effect of geometrical parameters on the effective elastic modulus for an X-type lattice truss panel structure

2018 ◽  
Vol 25 (6) ◽  
pp. 1135-1144
Author(s):  
Qian Zhang ◽  
Wenchun Jiang ◽  
Yanting Zhang
Keyword(s):  
Elastic Modulus ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Base Material ◽  
Sheet Thickness ◽  
High Strength ◽  
Effective Elastic Modulus ◽  
Homogenization Method ◽  
Clear Correlation ◽  
Geometrical Parameters

AbstractThe lattice truss panel structure (LTPS), which is a high strength material with high efficiency of heat transfer, has a good potential to be used as compact heat exchanger. The core of LTPS is a periodic porous structure, and the effective elastic modulus (EEM) will be different from the base material. It is essential to calculate the EEM for the design of this type of heat exchanger. This paper presents a study on the EEM of X-type LTPS by homogenization method, which has been verified by finite element method (FEM). It reveals that the effects of seven geometrical parameters of the X-type LTPS on EEM are not identical, and the relationship between the seven parameters and EEM has been established. Results calculated by homogenization method and FEM show a good agreement. The EEM decreases with the increase of truss length, stamping angle, shearing angle and node length, while it increases with the increase of truss width, truss thickness and face sheet thickness. Unlike the conventional foam material, there is no clear correlation between the EEM and the relative density, and a formula has been fitted to calculate the EEM of LTPS.

Design and Analysis of a High Temperature Particulate Hoist for Proposed Particle Heating Concentrator Solar Power Systems

2016 ◽  
Author(s):  
Kenzo K. D. Repole ◽  
Sheldon M. Jeter
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Solar Power ◽  
Low Cost ◽  
Cost Effective ◽  
Performance Model ◽  
Electricity Production ◽  
Maintenance Cost ◽  
Particle Heating

The central receiver power tower (CRPT) with a particle heating receiver (PHR) is a form of concentrating solar power (CSP) system with strong potential to achieve high efficiency at low cost and to readily incorporate cost-effective thermal energy storage (TES). In such a system, particulates are released into the PHR, and are heated to high temperature by concentrated solar radiation from the associated heliostat field. After being heated, the particles will then typically flow into the hot bin of the TES. Particulates accumulated in the hot bin can flow through a heat exchanger to energize a power generation system or be held in the hot TES storage bin for later use such as meeting a late afternoon peak demand or even overnight generation. Particles leaving the heat exchanger are held in the low temperature bin of the TES. A critical component in such a PHR system is the particle lift system, which must transport the particulate from the lower temperature TES bin back to the PHR. In our baseline 60 MW-thermal (MW-th) design, the particulate must be lifted around 70 m at the rate of 128 kg/s. For the eventual commercial scale system of a 460 MW-th design the particulate must be lifted around 138 m at the rate of 978 kg/s. The obvious demands on this subsystem require the selection and specification of a highly efficient, economical, and reliable lift design. After an apparently exhaustive search of feasible alternatives, the skip hoist was selected as the most suitable general design concept. While other designs have not been dismissed, our currently preferred somewhat more specific preliminary design employs a Kimberly Skip (KS) in a two-skip counterbalanced configuration. This design appears to be feasible to fabricate and integrate with existing technology at an acceptably low cost per MW-th and to promise high overall energy use efficiency, long service life, and low maintenance cost. A cost and performance model has been developed to allow optimization of our design and the results of that study are also presented. Our developed design meets the relevant criteria to promote cost effective CSP electricity production.

Preliminary Study on Features of Key Components for HTGR Helium Turbine System

2012 ◽  
Author(s):  
Haoran Hao ◽  
Xiaoyong Yang ◽  
Jie Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Pressure Drop ◽  
High Efficiency ◽  
Reactor Power ◽  
Moment Of Inertia ◽  
Outlet Temperature ◽  
Compact Structure ◽  
Rotary Machinery ◽  
The Moment

High temperature gas cooled reactor (HTGR) is featured by inherent safety. With high outlet temperature, HTGR is of potentially economical competitiveness. Helium turbine system can take advantage of high temperature helium to achieve high efficiency as well as compact structure, with development perspective. Key components of HTGR helium turbine system include rotary machinery such as turbo compressor and motor/generator, and heat transfer components (i.e. precooler, intercooler, recuperator and nuclear reactor). Due to the closed cycle, the features of key components are not independent. This paper preliminary explores the inherent relationships among features of key components, especially changing with reactor power. For heat transfer components, the general relationship between pressure drop and the effectiveness of heat transfer is analyzed. Furthermore, it is found that the pressure drop in recuperator, precooler and inter-cooler depends on the reactor power with engineering constraints. Besides, There exists the approximate squared relation between power and pressure drop in heat exchangers. For rotary machinery, it is found that the moment of inertia is the function of reactor power. For example, the moment of inertia of motor/generator is proportional to the reactor power. The relationship between moment of inertia of turbo-compressors and reactor power is more complex. This study is expected to be helpful to the design of key components for HTGR helium turbine system and can be applied to analyze the cycle’s dynamic characteristics.

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

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