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eBook An Investigation of the Characteristics of Regenerative Heat Exchangers epub

by Timothy J. Murphy

eBook An Investigation of the Characteristics of Regenerative Heat Exchangers epub
  • ISBN: 1423577957
  • Author: Timothy J. Murphy
  • Genre: No category
  • Language: English
  • Publisher: Storming Media (1996)
  • ePUB size: 1898 kb
  • FB2 size 1693 kb
  • Formats mbr mobi txt lit


The exchangers are modeled as porous media.

The exchangers are modeled as porous media. As such, for each exchanger shape, a Representative Elementary Volume (REV), which represents a unit cell of the exchanger, is developed. The flow through the REV is simulated with periodic velocity and thermal boundary conditions, using the commercial CFD software ANSYS FLUENT.

A comparison of the thermal attributes of different heat transfer surfaces shows a large potential to improve regenerators with respect to the . Rühlich . Quack H. (2002) Investigations on Regenerative Heat Exchangers. eds) Cryocoolers 10. Springer, Boston, MA.

A comparison of the thermal attributes of different heat transfer surfaces shows a large potential to improve regenerators with respect to the ratio between pressure drop and heat transfer.

A regenerative heat exchanger, or more commonly a regenerator, is a type of heat exchanger where heat from the hot fluid is intermittently stored in a thermal storage medium before it is transferred to the cold fluid. To accomplish this the hot fluid is brought into contact with the heat storage medium, then the fluid is displaced with the cold fluid, which absorbs the heat.

DTIC Archive, Murphy, Timothy J, AIR Force Inst OF Tech Wright-Patterson AFB OH, Heat Exchangers, Sponges, Transients . The effectiveness of the regenerators is also adversely affected by the rolling.

DTIC Archive, Murphy, Timothy J, AIR Force Inst OF Tech Wright-Patterson AFB OH, Heat Exchangers, Sponges, Transients, Ratios, Temperature, Thickness, Experimental Data, Integrated Systems, Reduction, Time, Surfaces, Fortran, Delay, Regenerative Cooling, Calibration, Computer Files, Friction, Inlets, Stacking, Heat Transfer Coefficients, Regeneration(Engineering), Heat Transfer, Mathematical Models .

The efficiency of regenerative cryocoolers like Gifford-McMahon-, Stirling . Plate-Fin Heat Exchangers- Guide to their Specification and Use, HTFS publication 1990, p. .

The efficiency of regenerative cryocoolers like Gifford-McMahon-, Stirling-, and Pulse Tube refrigerators depends to a large degree on the performance of the regenerators. This performance is on one hand determined by the heat capacity of the matrix. Whereas the characteristic length, which is used in Nu and Re, cancels out in the definition of j, one has to make a choice for the velocity applied in the Reynolds number. Nigen et a. 3-D Flow Model for Cryocooler Regenerators, Proc. 9th International Cryocooler Conference, Plenum Press, New York, 1997, p. 451.

Regenerative Heat Exchanger. This can be done by transferring heat (. In general, the heat exchangers used in regeneration may be classified as either regenerators or recuperators. Regenerator (Regenerative Heat Exchanger) is a type of heat exchanger where heat from the hot fluid is intermittently stored in a thermal storage medium before it is transferred to the cold fluid. partially expanded steam) from certain sections of the steam turbine, which is normally well above the ambient temperature, to the feedwater. This process is known as heat regeneration and a variety of heat regenerators can be used for this purpose.

Performance characteristics of a tubular regenerative heat exchanger. Excellent summaries of the extensive investigations on convective heat transfer to and from gases flowing in tubes may be found in I1CAda.

In conjunction with theoretical heat exchange model, experimental investigations have been conducted for a coupled system of Selective Catalytic Reduction (SCR) and Regenerative Heat Exchange (RHE), to reduce nitrogen oxides (NOx) from coal-fired boilers and High.

In conjunction with theoretical heat exchange model, experimental investigations have been conducted for a coupled system of Selective Catalytic Reduction (SCR) and Regenerative Heat Exchange (RHE), to reduce nitrogen oxides (NOx) from coal-fired boilers and High Temperature Air Combustion (HiTAC) furnaces. Results indicate there is no effect of catalysis reactions on heat transfer; catalysts serve the function of heating elements. The outlet NO concentration periodically decreased in an almost linear fashion.

Often flow is realized as a combination where the two fluids move in different patterns combined by same-way, oppositeway and cross flow, thus creating different temperature profiles. There are also many types of heatexchangers which are different in their construction and operation (tubular, plate and spiral)

Keywords: regenerative heat exchanger, fan head-throttling characteristic for direct and reverse supply, nozzle aerodynamic resistance, regenerator thermal efficiency. This work is licensed under a Creative Commons rcial . International License.

Keywords: regenerative heat exchanger, fan head-throttling characteristic for direct and reverse supply, nozzle aerodynamic resistance, regenerator thermal efficiency. Lomonosova 9, office.

This is a AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report number is A506013. The abstract provided by the Pentagon follows: The objective of the current research was to investigate the effects of reducing screen thickness on the volume and compactness factor of stacked, wire-screen regenerators. An improved transient step-change method was devised which integrated experimental data with a numerical model of the flow to determine the heat transfer coefficient and friction factor. The improvements to the approach are: (1) the measured inlet temperature trace is used, (2) the heat transfer coefficient is based on a parameter called the sponge effect delay time, and (3) the important effect of the tube surrounding the matrix is included in the numerical model. The data show that the heat transfer is the same for reduced thickness screens as it is for unrolled screens once the decrease in surface area caused by rolling the screens is taken into account. However, the friction factor increases, particularly for a 50% reduction in screen thickness. Consequently, the ratio of Colburn factor to friction factor, the compactness factor, decreases as the thickness of the screens decrease. The effectiveness of the regenerators is also adversely affected by the rolling.
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