Review of Computer Simulations of Regenerative Heat Exchangers

1978 ◽  
Vol 11 (8) ◽  
pp. 309-312
Author(s):  
A. J. Willmott
Keyword(s):  
Heat Exchanger ◽  
Recent Work ◽  
Computer Simulations ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Design Criteria ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Fuel Savings

Early models of the stationary performance of the regenerative heat exchanger are discussed together with more recent work in which the behaviour under chronologically varying operating conditions is simulated. The need is presented for better control facilities and possibly new design criteria if fuel savings in regenerative heat exchanger non-stationary operations are to be effected.

Estimating ASME Section III and VIII Heat Exchanger Nozzle Loads

2009 ◽  
Author(s):  
L. Ike Ezekoye ◽  
Colin Arnold
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Power Plant ◽  
Material Properties ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Design Criteria ◽  
Physical Geometry ◽  
External Forces ◽  
Stress Criteria

Heat Exchange Institute (HEI) Standards for Power Plant Heat Exchangers, 4th Edition provides guidance on how to estimate the nozzle loads of cylindrical shells. The procedure covered in one of the appendices of the document relies on WRC Bulletin 107 methodology which uses internal pressure, physical geometry and material properties to estimate external forces and moments. The forces and moments are the limiting loads when the heat exchanger material is taken to yield. The material yield defines the range of possible load combinations that will meet the design criteria. However, for operability, the design criteria sometimes may differ from the yield but usually is based on heat exchanger supplier experience. This paper provides a way to estimate heat exchanger nozzle loads that more closely reflect operating conditions that take into account supplier experience. In this paper, generalized load formulae are developed for the nozzles. The formulae are iteratively solved to meet the stress criteria based on supplier experience. The resultant loads are evaluated using WRC Bulletin 107 to ensure that the loads are bounded by the acceptance criteria. Unbounded loads are rejected and reiterated until the loads are acceptable.

Thermodynamic Analysis of Part-Flow Cycle Supercritical CO2 Gas Turbines

2008 ◽  
Author(s):  
Motoaki Utamura
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Expansion Ratio ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pinch Point ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Flow Cycle ◽  
Cycle Efficiency

Cycle characteristics of closed gas turbines using super critical carbon dioxide as a working fluid are investigated. It is found an anomalous behavior of physical properties of CO2 at pseudo-critical point may limit heat exchange rate of a regenerative heat exchanger due to the presence of pinch point inside the regenerative heat exchanger. Taking such pinch problem into consideration, the cycle efficiency of Brayton cycle is assessed. Its value is found limited to 39% degraded by 8% compared with the case without the pinch present inside. As an alternative a part flow cycle is investigated and its operable range has been identified. It is revealed that the part flow cycle is effective to recover heat transfer capability and may achieve the cycle thermal efficiency of 45% under maximum operating conditions of 20MPa and 800K. Optimal combination of turbine expansion ratio and a part flow ratio is 2.5 and 0.68 respectively. Parametric study is carried out. In neither compressor nor turbine, deteriorated adiabatic efficiency may affect cycle efficiency significantly. However, pressure drop characteristics of heat exchangers govern the cycle efficiency.

Thermodynamic Analysis of Part-Flow Cycle Supercritical CO2 Gas Turbines

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Motoaki Utamura
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Expansion Ratio ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pinch Point ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Flow Cycle ◽  
Cycle Efficiency

Cycle characteristics of closed gas turbines using supercritical carbon dioxide as a working fluid are investigated. It is found that an anomalous behavior of the physical properties of CO2 at the pseudocritical point may limit the heat exchange rate of a regenerative heat exchanger due to the presence of a pinch point inside the regenerative heat exchanger. Taking such a pinch problem into consideration, the cycle efficiency of the Brayton cycle is assessed. Its value is found to be limited to 39% degraded by 8% compared with the case without the pinch present inside. As an alternative, a part-flow cycle is investigated and its operable range has been identified. It is revealed that the part-flow cycle is effective to recover heat transfer capability and may achieve the cycle thermal efficiency of 45% under maximum operating conditions of 20 MPa and 800 K. Optimal combination of turbine expansion ratio and a part-flow ratio is 2.5 and 0.68, respectively. Parametric study is carried out. In neither compressor nor turbine, deteriorated adiabatic efficiency may affect cycle efficiency significantly. However, pressure drop characteristics of heat exchangers govern the cycle efficiency.

A Regenerative Heat Exchanger for Livestock Buildings

1984 ◽  
Vol 27 (5) ◽  
pp. 1505-1510
Author(s):  
W. P. Lampman ◽  
E. B. Moysey
Keyword(s):  
Heat Exchanger ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Livestock Buildings

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

2021 ◽  
Vol 23 ◽  
pp. 42-64
Author(s):  
Boris Basok ◽  
Ihor Bozhko ◽  
Maryna Novitska ◽  
Aleksandr Nedbailo ◽  
Myroslav Tkachenko
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ventilation System ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Operational Parameters ◽  
Cross Sectional ◽  
Distinctive Features ◽  
Sectional Shape ◽  
Experimental Bench

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

ADVANCED TYPES OF CHECKERWORK OF REGENERATIVE HEAT EXCHANGERS FOR GLASS FURNACES

2021 ◽  
pp. 3-10
Author(s):  
O. Koshelnik ◽  
S. Hoisan
Keyword(s):  
Phase Transition ◽  
Heat Exchangers ◽  
Heat Storage ◽  
Point Of View ◽  
Operating Conditions ◽  
Flue Gases ◽  
Regenerative Heat ◽  
Exchange Processes ◽  
Glass Furnaces ◽  
Refractory Bricks

One of the ways to increase glass furnaces energy efficiency is to apply heat exchangers for flue gases thermal potential utilization. Flue gases losses is up to 25-40 % of the total amount of heat supplied in the furnace. These losses are influences by such factors as fuel type, furnace and burners design and manufactured product type. Regenerative heat exchangers with various types of heat storage packing is more efficient for high-power furnaces. Such types of regenerator checkerwork as Cowper checkerwork, two types of Siemens checkerwork, Lichte checkerwork and combined checkerwork have already been sufficiently researched, successfully applied and widely used for glass furnaces of various designs. All of its are made of standard refractory bricks. Basket checkerwork and cruciform checkerwork that are made of fused-cast molded refractory materials have been widely used recently as well. Further improvement of regenerative heat exchangers thermal efficiency only by replacing the checkerwork does not seem possible unless their size being increased. But this enlarging is not always realizable during the modernization of existing furnaces. From this point of view heat storage elements with a phase transition, where metal salts and their mixtures are used as a fusible agent look promising for glass furnaces. These elements can accumulate additional amount of heat due to phase transition, which allows to increase significantly heat exchanger thermal rating without its size and operating conditions changing. However, it is necessary to carry out additional studies of this type of checkerwork dealing with analysis of complex unsteady heat exchange processes in regenerators and selection of appropriate materials that satisfy the operating conditions of regenerative heat exchangers so that the checkerwork can be widely used for glass furnaces.

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.

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