scholarly journals STUDY OF THE EFFECT OF OPERATING AND DESIGN PARAMETERS OF OUTBOARD COOLER ON HEAT TRANSFER IN THE TUBE SPACE

2017 ◽  
Vol 9 (5) ◽  
pp. 1040-1050
Author(s):  
Sergey N. Tkach ◽  
Keyword(s):  
Heat Transfer ◽  
Design Parameters ◽  
Tube Space

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.

A Thermal Model to Predict Tool Temperature in Machining of Ti-6Al-4V Alloy With an Atomization-Based Cutting Fluid Spray System

2016 ◽  
Author(s):  
Asif Tanveer ◽  
Deepak Marla ◽  
Shiv G. Kapoor
Keyword(s):  
Heat Transfer ◽  
Interaction Model ◽  
Spray Cooling ◽  
Droplet Surface ◽  
Cutting Fluid ◽  
Design Parameters ◽  
Transfer Model ◽  
Tool Temperature ◽  
Spray System ◽  
Heat Transfer Phenomenon

In this study a heat transfer model of machining of Ti-6Al-4V under the application of atomization-based cutting fluid spray coolant is developed to predict the temperature of the cutting tool. Owing to high tool temperature involved in machining of Ti-6Al-4V, the model considers film boiling as the major heat transfer phenomenon. In addition, the design parameters of the spray for effective cooling during machining are derived based on droplet-surface interaction model. Machining experiments are conducted and the temperatures are recorded using the inserted thermocouple technique. The experimental data are compared with the model predictions. The temperature field obtained is comparable to the experimental results, confirming that the model predicts tool temperature during machining with ACF spray cooling satisfactorily.

MHD and nonlinear thermal radiation effects on hybrid nanofluid past a wedge with heat source and entropy generation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fazle Mabood ◽  
Anum Shafiq ◽  
Waqar Ahmed Khan ◽  
Irfan Anjum Badruddin
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Heat Source ◽  
Thermal Radiation ◽  
Entropy Generation ◽  
Entropy Generation Rate ◽  
Design Parameters ◽  
Hybrid Nanofluid ◽  
Nonlinear Thermal Radiation ◽  
Content Type

Purpose This study aims to investigate the irreversibility associated with the Fe3O4–Co/kerosene hybrid-nanofluid past a wedge with nonlinear radiation and heat source. Design/methodology/approach This study reports the numerical analysis of the hybrid nanofluid model under the implications of the heat source and magnetic field over a static and moving wedge with slips. The second law of thermodynamics is applied with nonlinear thermal radiation. The system that comprises differential equations of partial derivatives is remodeled into the system of differential equations via similarity transformations and then solved through the Runge–Kutta–Fehlberg with shooting technique. The physical parameters, which emerges from the derived system, are discussed in graphical formats. Excellent proficiency in the numerical process is analyzed by comparing the results with available literature in limiting scenarios. Findings The significant outcomes of the current investigation are that the velocity field uplifts for higher velocity slip and magnetic strength. Further, the heat transfer rate is reduced with the incremental values of the Eckert number, while it uplifts with thermal slip and radiation parameters. An increase in Brinkmann’s number uplifts the entropy generation rate, while that peters out the Bejan number. The results of this study are of importance involving in the assessment of the effect of some important design parameters on heat transfer and, consequently, on the optimization of industrial processes. Originality/value This study is original work that reports the hybrid nanofluid model of Fe3O4–Co/kerosene.

Flow Structure and Heat Transfer in Stagnation Flow CVD Reactor

2010 ◽  
Author(s):  
Nasir Memon ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Flow Structure ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Flow Reactor ◽  
Chemical Vapor ◽  
Design Parameters ◽  
Stagnation Flow ◽  
Inlet Length ◽  
The Impact

An experimental study is undertaken to investigate the flow structure and heat transfer in a stagnation flow Chemical Vapor Deposition (CVD) reactor at atmospheric pressure. It is critical to develop models that predict flow patterns in such a reactor to achieve uniform deposition across the substrate. Free convection can negatively affect the gas flow as cold inlet gas impinges on the heated substrate, leading to vortices and disturbances in the normal flow path. This experimental research will be used to understand the buoyancy-induced and momentum-driven flow structure encountered in an impinging jet CVD reactor. Investigations are conducted for various operating and design parameters. A modified stagnation flow reactor is built where the height between the inlet and substrate is reduced when compared to a prototypical stagnation flow reactor. By operating such a reactor at certain Reynolds and Grashof numbers it is feasible to sustain smooth and vortex free flow at atmospheric pressure. The modified stagnation flow reactor is compared to other stagnation flow geometries with either a varied inlet length or varied heights between the inlet and substrate. Comparisons are made to understand the impact of such geometric changes on the flow structure and the thermal boundary layer. In addition, heat transfer correlations are obtained for the substrate temperature. Overall, the results obtained provide guidelines for curbing the effects of buoyancy and for improving the flow field to obtain greater film uniformity when operating a stagnation flow CVD reactor at atmospheric pressure.

The Effect of Wall Thermal Boundary Condition on Natural Convective Shutdown Cooling in a Gas Turbine

2021 ◽  
pp. 1-25
Author(s):  
Daniel Fahy ◽  
Peter Ireland
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Gradient ◽  
Low Cost ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Design Parameters ◽  
Complex Nature ◽  
Convective Boundary ◽  
Thermocouple Probe

Abstract As a civil gas turbine cools down, asymmetric natural convective heat transfer causes the bottom sector of the rotor to cool faster than the top; this circumferential thermal gradient can potentially cause the shaft to deflect – a phenomenon called thermal or rotor bow. Rotor bow is tremendously difficult to predict due to its dependence on a number of engine design parameters, in addition to the complex nature of natural convective flows. A novel experimental facility has been developed to gain further understanding into shutdown cooling of a gas turbine. The scope of this paper is to quantify the effect of basic design features on natural convective cooling in an engine annulus during shut-down. In addition to this, a low-cost, robust thermocouple probe has been developed and validated, which allows for accurate temperature measurements in a natural convective boundary layer. An extensive experimental campaign has been completed. The key finding is that the local radial wall temperature difference was found to be the most influential parameter on the local heat transfer. Non-isothermal walls did not alter the overall distribution of the inner wall equivalent conductivity. This was true for both cylindrical and conical sections. Therefore, the mean surface heat transfer for non-isothermal inner and outer profiles, within the range −0.4<Ra/RaLc <0.4, where the thermal gradient is negative in the clockwise from top-dead- centre, can be predicted using isothermal correlations for RaLc < 5.0 × 105 and Dr < = 1.5.

Development of a Computer Program for the Numerical Investigation of Heat Transfer in a Gasketed Plate Heat Exchanger

2010 ◽  
Author(s):  
Gizem Gulben ◽  
Selin Aradag ◽  
Nilay Sezer-Uzol ◽  
Ufuk Atamturk
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Computer Program ◽  
Working Conditions ◽  
Convective Heat Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Design Parameters ◽  
Outlet Temperature ◽  
Pressure Drops ◽  
Plate Heat

In this study, a computer program is developed to calculate characteristics of a Chevron type gasketed plate heat exchanger (CTGPHEX) such as: the number of plates, the effective surface area and total pressure drops. The main reason to prefer the use of CTGPHEXs to other various types of heat exchangers is that the heat transfer efficiency is much higher in comparison. Working conditions such as the flow rates and inlet and outlet temperature of both flow sides and plate design parameters are used as an input in the program. The Logarithmic Mean Temperature Method and the different correlations for convective heat transfer coefficient and Fanning factor that are found in the literature are applied to calculate the minimum necessary effective heat transfer area, the number of plate and pressure drops due to friction for both fluid sides of fulfill the desired heat transfer rate. This Turkish / English language optioned user friendly computer program is targeted to be used in domestic companies to design and select CTGPHEXs for any desired working conditions.

scholarly journals Steady state analysis of regular hollow pyramidal radiating fin with triangular cross-section

2015 ◽  
Vol 19 (1) ◽  
pp. 59-68
Author(s):  
Vijaikrishnan Venkataramanan ◽  
Ramakrishnan Madhavaneswaran ◽  
Siva Shanmugam
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Cross Section ◽  
Working Conditions ◽  
Unit Mass ◽  
Design Parameters ◽  
Steady State Analysis ◽  
Fin Efficiency ◽  
Triangular Cross Section ◽  
Optimum Parameters

A new configuration for space radiator is proposed introducing a fin of regular hollow pyramidal shape with triangular cross section, giving a higher improvement in heat loss per unit mass than that of other corresponding configurations previously proposed under same working conditions. The significance of the present configuration and its advantage over other regular hollow configurations are discussed and effect of various design parameters on heat transfer is analyzed in presence of radiation interaction with an isothermal base attached to it. Optimum parameters are identified for which improvement in heat loss per unit mass is the maximum. It is found that the fin efficiency decreases with increase in the emissivity & height of the fin and increases with increase in thickness & top radius of the fin. Correlations are presented for optimum design parameters, optimum improvement in heat loss per unit mass and fin efficiency.

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