Thermo-Mechanical Design of a High-Temperature Silicon Carbide Micro-Channel Heat Exchanger

2003 ◽  
Author(s):  
Merrill A. Wilson ◽  
Steven M. Quist
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Mechanical Design ◽  
Mechanical Degradation ◽  
Micro Channel ◽  
Power Cycles ◽  
Microchannel Heat Exchanger ◽  
Operating Environments

Efficiency and emissions of advanced gas turbine power cycles can be improved by incorporating high-temperature ceramic heat exchangers (see Figure 1). In cooperation with the DOE, preliminary development and testing of SiC based structures has been completed. This program has focused on four initial areas: thermo-mechanical degradation as a function of the chemical operating environments, design of a layered microchannel heat exchanger, thermo-mechanical testing and analysis of these structures, and fabrication development through rapid prototyping techniques.

Design and Development of a Low-Cost, High Temperature Silicon Carbide Micro-Channel Recuperator

2005 ◽  
Author(s):  
Merrill A. Wilson ◽  
Kurt Recknagle ◽  
Kriston Brooks
Keyword(s):  
Heat Transfer ◽  
Silicon Carbide ◽  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Ceramic Materials ◽  
Micro Channel ◽  
Micro Channels ◽  
Micro Turbine

Typically, ceramic micro-channel devices are used for high temperature heat exchangers, catalytic reactors, electronics cooling, and processing of corrosive streams where the thermomechanical benefits of ceramic materials are desired. These benefits include: high temperature mechanical and corrosion properties and tailorable material properties such as thermal expansion, electrical conductivity and thermal conductivity. In addition, by utilizing Laminated Object Manufacturing (LOM) methods, inexpensive ceramic materials can be layered, featured and laminated in the green state and co-sintered to form monolithic structures amenable to mass production. In cooperation with the DOE and Pacific Northwest National Labs, silicon carbide (SiC) based micro-channel recuperator concepts are being developed and tested. The performance benefits of a high temperature, micro-channel heat exchanger are realized from the improved thermal efficiency of the high temperature cycles and the improved effectiveness of micro-channels for heat transfer. In designing these structures, the heat and mass transfer within the micro-channels are being analyzed with heat transfer models, computational fluid dynamics models and validated with experimental results. As an example, a typical micro-turbine cycle was modified and modeled to incorporate this ceramic recuperator and it was found that the overall thermal efficiency of the micro-turbine could be improved from about 27% to over 40%. Process improvements require technical advantages and cost advantages. These LOM methodologies have been based on well-proven industry standard processes where labor, throughput and capital estimates have been tested. Following these cost models and validation at the prototype scale, cost estimates were obtained. For the micro-turbine example, cost estimates indicate that the high-temperature SiC recuperator would cost about $200 per kWe. The development of these heat exchangers is multi-faceted and this paper focuses on the design optimization of a layered micro-channel heat exchanger, its performance testing, and fabrication development through LOM methodologies.

Thermo-Mechanical Design of Brazed Plate-Fins Heat Exchanger Based on Finite Element Modeling Using Homogenization Techniques

2009 ◽  
Author(s):  
Johan Dib ◽  
Ivan Lewon ◽  
Boris Martin
Keyword(s):  
Finite Element ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Mechanical Design ◽  
Periodic Structures ◽  
Software Tool ◽  
Design Criteria ◽  
Base Metals ◽  
The Core ◽  
Aluminum Base

Using classical Finite Element (FE) tools to model heat exchangers emphasizes the need to elaborate specific methods to reduce the size of the numerical problem. Among these methods, homogenization techniques can be adapted and used for Brazed Aluminum Plate-Fins Heat Exchangers (BAHX) including layers of periodic structures. Actually the core is formed by stacking single layers consisting of periodic corrugated fins, side-bar and parting sheets which are all made of aluminum base metals, and brazed in a furnace. So in this paper a global methodology of BAHX modeling and design is presented. It integrates homogenization techniques to perform FE calculation and localization techniques to allow applying the appropriate design criteria. Finally, to validate this methodology, results are then compared on a basic heat exchanger modeled both by classical FE tools and a dedicated software tool encapsulating both homogenization and localization techniques.

Hydrodynamic and Thermal Performance of a Vapor-Venting Microchannel Copper Heat Exchanger

2008 ◽  
Author(s):  
Milnes P. David ◽  
Amy Marconnet ◽  
Kenneth E. Goodson
Keyword(s):  
Heat Exchanger ◽  
Carbon Fiber ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Exchangers ◽  
Single Phase ◽  
Two Phase ◽  
Microchannel Heat Exchanger ◽  
Large Pressure ◽  
Dry Out

Two-phase microfluidic cooling has the potential to achieve low thermal resistances with relatively small pumping power requirements compared to single-phase heat exchanger technology. Two-phase cooling systems face practical challenges however, due to the instabilities, large pressure drop, and dry-out potential associated with the vapor phase. Our past work demonstrated that a novel vapor-venting membrane attached to a silicon microchannel heat exchanger can reduce the pressure drop for two-phase convection. This work develops two different types of vapor-venting copper heat exchangers with integrated hydrophobic PTFE membranes and attached thermocouples to quantify the thermal resistance and pressure-drop improvement over a non-venting control. The first type of heat exchanger, consisting of a PTFE phase separation membrane and a 170 micron thick carbon-fiber support membrane, shows no improvement in the thermal resistance and pressure drop. The results suggest that condensation and leakage into the carbon-fiber membrane suppresses venting and results in poor device performance. The second type of heat exchanger, which evacuates any liquid water on the vapor side of the PTFE membrane using 200 ml/min of air, reduces the thermal resistance by almost 35% in the single-phase regime in comparison. This work shows that water management, mechanical and surface properties of the membrane as well as its attachment and support within the heat exchanger are all key elements of the design of vapor-venting heat exchangers.

Heat and Mass Transfer Design of a Silicon Carbide Micro-Channel Heat Exchanger

2003 ◽  
Author(s):  
Merrill A. Wilson ◽  
Michele Bullough ◽  
Kriston Brooks ◽  
Kurt Recknagle
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Unit Volume ◽  
Micro Channel ◽  
System Efficiency ◽  
Uniform Temperature ◽  
Power Cycles ◽  
Ceramic Recuperator ◽  
Improve Heat Transfer ◽  
Higher Temperature

Efficiency and emissions of advanced gas turbine power cycles can be improved by incorporating high-temperature ceramic heat exchangers. In cooperation with the DOE, a highly effective microchannel ceramic recuperator for a microturbine is under development. In this recuperator, the use of microchannel architecture will improve heat transfer and provide a more uniform temperature distribution. This will result in overall higher productivity per unit volume compared to conventional hardware. The use of ceramic for the recuperator will allow higher temperature operation than available in conventional microturbines. Based on a model for a typical microturbine, these changes may improve the overall system efficiency from about 27% to over 40%.

Diffusion-Welded Microchannel Heat Exchanger for Industrial Processes

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Piyush Sabharwall ◽  
Denis E. Clark ◽  
Ronald E. Mizia ◽  
Michael V. Glazoff ◽  
Michael G. McKellar
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Design Method ◽  
Industrial Process ◽  
Industrial Applications ◽  
Thermal Design ◽  
Industrial Processes ◽  
Diffusion Welding ◽  
Microchannel Heat Exchanger ◽  
Increase Energy Efficiency

The goal of next generation reactors is to increase energy efficiency in the production of electricity and provide high-temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient industrial processes. Modern compact heat exchangers can provide high compactness, a measure of the ratio of surface area-to-volume of a heat exchange. The microchannel heat exchanger studied here is a plate-type, robust heat exchanger that combines compactness, low pressure drop, high effectiveness, and the ability to operate with a very large pressure differential between hot and cold sides. The plates are etched and thereafter joined by diffusion welding, resulting in extremely strong all-metal heat exchanger cores. After bonding, any number of core blocks can be welded together to provide the required flow capacity. This study explores the microchannel heat exchanger and draws conclusions about diffusion welding/bonding for joining heat exchanger plates, with both experimental and computational modeling, along with existing challenges and gaps. Also, presented is a thermal design method for determining overall design specifications for a microchannel printed circuit heat exchanger for both supercritical (24 MPa) and subcritical (17 MPa) Rankine power cycles.

Performance Optimization of Compact Ceramic High Temperature Heat Exchangers

2007 ◽  
Author(s):  
Q. Y. Chen ◽  
M. Zeng ◽  
D. H. Zhang ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Performance Optimization ◽  
Heat Exchangers ◽  
Radiation Heat Transfer ◽  
Surface Radiation ◽  
Radiation Heat ◽  
High Temperature Side ◽  
Temperature Heat

In the present paper, the compact ceramic high temperature heat exchangers with parallel offset strip fins and inclined strip fins (inclined angle β = 0∼70°) are investigated with CFD method. The numerical simulations are carried out for high temperature (1500°C), without and with radiation heat transfer, and the periodic boundary is used in transverse direction. The fluid of high temperature side is the standard flue gas. The material of heat exchanger is SiC. NuS-G.R(with surface and gaseous radiation heat transfer) is averagely higher than NuNo.R (without radiation heat transfer) by 7% and fS-G.R is averagely higher than fNo.R by 5%. NuS-G.R(with surface and gaseous radiation heat transfer) is averagely higher than NuS.R (with only surface radiation heat transfer) by 0.8% and fS-G.R is averagely higher than fS.R by 3%. The thermal properties have significantly influence on the heat transfer and pressure drop characteristics, respectively. The heat transfer performance of the ceramic heat exchanger with inclined fins (β = 30°) is the best.

The Effectiveness-NTU Relationship of Microchannel Counter Flow Heat Exchangers With Axial Heat Conduction

2007 ◽  
Author(s):  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Microchannel Heat Exchanger ◽  
Axial Temperature ◽  
Axial Heat ◽  
Relationship Of ◽  
End Wall ◽  
Axial Heat Conduction

In this paper the effect of axial heat conduction on the thermal performance of a microchannel heat exchanger with non-adiabatic end walls is studied. The two ends of the wall separating the coolant are assumed to be subjected to boundary condition of the first kind. As the end walls are not insulated heat transfer between the microchannel heat exchanger and its surroundings occur. Analytical equations have been formulated for predicting the axial temperature of the coolants and the wall as well as for determining the effectiveness of both fluids. The effectiveness of the fluids has been found to depend on the NTU, axial heat conduction parameter and end wall temperatures. The heat transfer through the end walls have been expressed in nondimensional terms. The nondimensional heat transfer from both ends of the wall also depends on the axial heat conduction parameter and temperature gradient at the end walls. A new parameter, performance factor, has been proposed for comparing the variation in effectiveness due to axial heat conduction coupled with heat transfer with the effectiveness without axial heat conduction. The effectiveness of both the hot and cold fluid for several cases of end wall temperatures and axial heat conduction parameter are analyzed in this paper for better understanding of heat transfer dynamics of microchannel heat exchangers.

scholarly journals High-Temperature Particle Heat Exchanger for sCO2 Power Cycles (Award 30342).

2020 ◽  
Author(s):  
Matthew Carlson ◽  
Kevin Albrecht ◽  
Clifford Ho ◽  
Hendrik Laubscher ◽  
Francisco Alvarez
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Power Cycles

Viability of Ceramic High Temperature Heat Exchangers in NGNP Applications

2008 ◽  
Author(s):  
Merrill A. Wilson ◽  
Charles Lewinsohn ◽  
James Cutts ◽  
Yitung Chen ◽  
Valery Ponyavin
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ceramic Materials ◽  
Reliability Models ◽  
Tube Heat Exchanger ◽  
Temperature Heat ◽  
Intermediate Heat Exchanger ◽  
Recent Developments ◽  
Higher Temperature

The recent developments in the energy industry have kindled renewed interest in producing energy more efficiently. This has motivated the development of higher temperature cycles and their associated equipment. In this paper we will discuss several design configurations coupled with the inherent properties of preferred ceramic materials to assess the viability and design reliability of ceramic heat exchangers for next generation high temperature heat exchangers. These analyses have been extended to conceptually compare the traditional shell and tube heat exchanger with shell and plate heat exchangers. These analyses include hydrodynamic, heat transfer, mechanical stress and reliability models applicable to an Intermediate Heat Exchanger (IHX) and Process Coupling Heat Exchangers. It was found that ceramic micro-channel heat exchanger designs proved to have the greatest reliability due to their inherent mechanical properties, minimal thermo-mechanical stresses while improving the performance efficiency in a compact footprint.

Packaging of High Frequency, High Temperature Silicon Carbide (SiC) Multichip Power Module (MCPM) Bi-directional Battery Chargers for Next Generation Hybrid Electric Vehicles

2012 ◽  
Vol 2012 (1) ◽  
pp. 001105-001115 ◽  
Author(s):  
Z. Cole ◽  
B. Passmore ◽  
B. Whitaker ◽  
A. Barkley ◽  
T. McNutt ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Power Density ◽  
Hybrid Electric Vehicle ◽  
Peak Power ◽  
Mechanical Design ◽  
Next Generation ◽  
Power Module ◽  
Modeling And Analysis ◽  
Hybrid Electric

The packaging design and development of an on-board bi-directional charger for the battery system of the next generation Toyota Prius plug-in hybrid electric vehicle (PHEV) will be presented in this paper. The charger implements a multichip power module (MCPM) packaging strategy. The Silicon Carbide (SiC) MCPM charger is capable of operating to temperatures in excess of 200°C and at switching frequencies in excess of 500 kHz, significantly reducing the overall size and weight of the system in comparison with Toyota's present silicon-based Prius charger. The present actively cooled Si charger is capable of delivering a peak power of 1kW at less than 90 percent efficiency, is limited to less than 50 kHz switching, and measures greater than 6.3 liters with a mass of 6.6 kg, resulting in a power density of 150 W/kg. The passively cooled SiC MCPM charger presented herein was designed to deliver a peak power of 5 kW at greater than 96% efficiency, while measuring less than 0.9 liters with a mass of 1 kg, resulting in a power density greater than 5 kW/kg. Thus, the novel SiC MCPM charger represents an increase in power density of more than 30×, a very significant power density achievement in size and weight for sensitive mobile applications such as PHEVs. This paper will discuss the overall mechanical design of the SiC MCPM charger, the finite-element modeling and analysis of thermal and stress considerations, characterization and parasitic analysis of the MCPM, and the development of high temperature solutions for SiC devices.

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