Energy Loss and Pumping Power Analysis of Fully Developed Laminar Convection in a Helical Coil

2007 ◽  
Author(s):  
Seeaidreza Javadinezhad ◽  
Zahra Asadikapourchali
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Exchange Process ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Helical Coil ◽  
Primary Concern ◽  
Pumping Power ◽  
Heat Exchanger Design ◽  
Laminar Convection

Energy loss characteristics of heat transfer and fluid flow due to forced convection of steady laminar flow of incompressible fluid in a helical coil is analysed. This paper analyses energy loss and pumping power in the fully developed laminar convection in a helical coil with constant wall heat flux. The important design parameters, including Reynolds number (Re), coil to tube radius (δ) and dimensional coil pitch (λ) are varied to investigate their influences on the energy loss and pumping power values. Amount of heat transfer is the primary concern in a heat exchanger design. The amount of energy loss during the heat exchange process has been investigated by introducing a new dimensionless number This dimensionless number has been defined as the energy loss to total heat transfer rate ratio. The energy loss dimensionless number behavior have been compared with entropy generation dimensionless number behavior for this problem.

Second Law and Energy Loss Analysis in a Turbulent Flow Through a Nozzle Type Duct

2005 ◽  
Author(s):  
S. R. Javadinejhad
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Exchange Process ◽  
Dimensionless Number ◽  
Inlet Temperature ◽  
Primary Concern ◽  
Loss Analysis ◽  
Heat Exchanger Design ◽  
Heat Exchange Process ◽  
Pattern Forming

Amount of heat transfer is the primary concern in a heat exchanger design. The amount of energy that has been destroyed during the heat exchange process has been investigated by introducing a new dimensionless number. Analyises of simpler systems are often useful to understand more important features of complex pattern forming processes in various field of science and technology. The entropy generation have been studied by use of new dimensionless number . This number defined as the ratio of total energy loss to total heat transfer across the duct length. The temperature dependence on the viscosity is taken into consideration and results have been derived for various L/D ratio, nozzle angles and inlet temperature.

Energy Loss and Entropy Generation Analysis in Fundamental Convective Heat Transfer Problems

2005 ◽  
Author(s):  
S. R. Javadinejhad
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Entropy Generation ◽  
Circular Cross Section ◽  
Dimensionless Number ◽  
Parallel Plates ◽  
Heat Transfer Characteristics ◽  
Total Heat Transfer ◽  
Transfer Problems ◽  
Steady Laminar

Energy loss characteristics of heat transfer and fluid flow due to forced convection of steady laminar flow of incompressible fluid inside channel with circular cross section and channel made of two parallel plates is analyzed. Energy loss profiles and heat transfer characteristics for different problems have been discussed. In each case energy loss due to heat transfer effect and fluid friction have been drived analytically. For energy loss calculations a new dimensionless number have been introduced that is the energy loss to total heat transfer rate ratio. The energy loss dimensionless number behavior have been compared with entropy generation dimensionless number behavior for various problems.

Inelastic Electron-Matter Interactions

1978 ◽  
Vol 36 (3) ◽  
pp. 259-267
Author(s):  
J. Silcox
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Chemical Structure ◽  
Inelastic Electron ◽  
Primary Concern ◽  
Unique Probe ◽  
Introductory Paper ◽  
Elastic Processes ◽  
Experimental Level ◽  
Inelastic Processes

In this introductory paper, my primary concern will be in identifying and outlining the various types of inelastic processes resulting from the interaction of electrons with matter. Elastic processes are understood reasonably well at the present experimental level and can be regarded as giving information on spatial arrangements. We need not consider them here. Inelastic processes do contain information of considerable value which reflect the electronic and chemical structure of the sample. In combination with the spatial resolution of the electron microscope, a unique probe of materials is finally emerging (Hillier 1943, Watanabe 1955, Castaing and Henri 1962, Crewe 1966, Wittry, Ferrier and Cosslett 1969, Isaacson and Johnson 1975, Egerton, Rossouw and Whelan 1976, Kokubo and Iwatsuki 1976, Colliex, Cosslett, Leapman and Trebbia 1977). We first review some scattering terminology by way of background and to identify some of the more interesting and significant features of energy loss electrons and then go on to discuss examples of studies of the type of phenomena encountered. Finally we will comment on some of the experimental factors encountered.

Conjugate Heat Transfer and Film Cooling of a Multi-Stage Cooling Scheme

2008 ◽  
Author(s):  
M. Ghorab ◽  
S. I. Kim ◽  
I. Hassan
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Density Ratio ◽  
Design Parameters ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Multi Stage ◽  
Internal Gap

Cooling techniques play a key role in improving efficiency and power output of modern gas turbines. The conjugate technique of film and impingement cooling schemes is considered in this study. The Multi-Stage Cooling Scheme (MSCS) involves coolant passing from inside to outside turbine blade through two stages. The first stage; the coolant passes through first hole to internal gap where the impinging jet cools the external layer of the blade. Finally, the coolant passes through the internal gap to the second hole which has specific designed geometry for external film cooling. The effect of design parameters, such as, offset distance between two-stage holes, gap height, and inclination angle of the first hole, on upstream conjugate heat transfer rate and downstream film cooling effectiveness performance are investigated computationally. An Inconel 617 alloy with variable properties is selected for the solid material. The conjugate heat transfer and film cooling characteristics of MSCS are analyzed across blowing ratios of Br = 1 and 2 for density ratio, 2. This study presents upstream wall temperature distributions due to conjugate heat transfer for different gap design parameters. The maximum film cooling effectiveness with upstream conjugate heat transfer is less than adiabatic film cooling effectiveness by 24–34%. However, the full coverage of cooling effectiveness in spanwise direction can be obtained using internal cooling with conjugate heat transfer, whereas adiabatic film cooling effectiveness has narrow distribution.

Acoustic meta-silencer: Toward enabling ultrawide-band air-permeable noise barrier

2021 ◽  
pp. 107754632110011
Author(s):  
Mohammad Javad Khodaei ◽  
Amin Mehrvarz ◽  
Reza Ghaffarivardavagh ◽  
Nader Jalili
Keyword(s):  
Heat Transfer ◽  
Design Methodology ◽  
Heat Transfer Performance ◽  
Transmission Loss ◽  
Design Parameters ◽  
Transfer Performance ◽  
Noise Mitigation ◽  
Acoustic Cavity ◽  
Road Map ◽  
Noise Barrier

In this article, we have first presented a metasurface design methodology by coupling the acoustic cavity to the coiled channel. The geometrical design parameters in this structure are subsequently studied both analytically and numerically to identify a road map for silencer design. Next, upon tuning the design parameters, we have introduced an air-permeable noise barrier capable of sound silencing in the ultrawide band of the frequency. It is has been shown that the presented metasurface can achieve +10 dB sound transmission loss from 170 Hz to 1330 Hz (≈3 octaves). Furthermore, we have numerically studied the ventilation and heat transfer performance of the designed metasurface. Enabling noise mitigation by leveraging the proposed metasurface opens up new possibilities ranging from residential and office noise reduction to enabling ultralow noise fan, propellers, and machinery.

The Energy-Saving Optimization of the Organic Heat Transfer Material Heater

2012 ◽  
Vol 455-456 ◽  
pp. 284-288
Author(s):  
Wei Li Gu ◽  
Jian Xiang Liu
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Flue Gas ◽  
Theoretical Basis ◽  
Operation Management ◽  
Exergy Loss ◽  
Irreversible Processes ◽  
Design Parameters ◽  
Gas Temperature

this paper studies the typical irreversible processes such as combustion and heat transfer with temperature difference based on the theory of thermodynamics, analyzes the influencing factors on exergy loss in irreversible processes, on the basis of this analysis, proposes the energy-saving optimization measures on design and operation management of the organic heat transfer material heater, and specially points out that in the design process, objective function can be constructed with the exergy loss as evaluation index to determine the outlet flue gas temperature of furnace and the flue gas temperature, and provides theoretical basis for the determination of design parameters.

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