Effect of Slip Velocity and Heat Transfer on the Condensed Phase Momentum Flux of Supersonic Nozzle Flows

1999 ◽  
Vol 122 (1) ◽  
pp. 14-19 ◽  
Author(s):  
S. A. Sherif ◽  
W. E. Lear ◽  
N. S. Winowich
Keyword(s):  
Heat Transfer ◽  
Momentum Flux ◽  
Slip Velocity ◽  
Figure Of Merit ◽  
Supersonic Nozzle ◽  
Nozzle Design ◽  
Gaseous Nitrogen ◽  
Liquid Phases ◽  
Nozzle Flows ◽  
Phase Momentum

One of the methods used for industrial cleansing applications employs a mixture of gaseous nitrogen and liquid water injected upstream of a converging-diverging nozzle located at the end of a straight wand assembly. The idea is to get the mixture to impact the surface at the maximum momentum flux possible in order to maximize the cleansing effectiveness. This paper presents an analysis geared towards this application in which the effects of slip and heat transfer between the gas and liquid phases are present. The model describes the liquid momentum flux (considered a figure of merit for cleansing) under a host of design conditions. While it is recognized that the emulsification mechanism responsible for cleansing is far more complicated than simply being solely dependent on the liquid momentum flux, the analysis presented here should prove useful in providing sufficiently accurate results for nozzle design purposes. [S0098-2202(00)01801-0]

scholarly journals Some nozzle flows found by the hodograph method

1959 ◽  
Vol 1 (1) ◽  
pp. 80-94 ◽  
Author(s):  
T. M. Cherry
Keyword(s):  
Exact Solutions ◽  
Two Dimensions ◽  
Nozzle Design ◽  
Perfect Gas ◽  
Field Equations ◽  
Rigid Boundary ◽  
Hodograph Method ◽  
Isentropic Flow ◽  
Fixed Boundaries ◽  
Nozzle Flows

For investigating the steady irrotational isentropic flow of a perfect gas in two dimensions, the hodograph method is to determine in the first instance the position coordinates x, y and the stream function ψ as functions of velocity compoments, conveniently taken as q (the speed) and θ (direction angle). Inversion then gives ψ, q, θ as functions of x, y. The method has the great advantage that its field equations are linear, so that it is practicable to obtain exact solutions, and from any two solutions an infinity of others are obtainable by superposition. For problems of flow past fixed boundaries the linearity of the field equations is usually offset by non-linearity in the boundary conditions, but this objection does not arise in problems of transsonic nozzle design, where the rigid boundary is the end-point of the investigation.

Analysis of the Impact of Specific Heat Ratio on Two-Dimensional Low Maher Number Nozzle Design

2014 ◽  
Vol 590 ◽  
pp. 546-550
Author(s):  
Zhi Qiang Fan ◽  
Hai Bo Yang ◽  
Fei Zhao ◽  
Rong Zhu ◽  
Dong Bai Sun
Keyword(s):  
Specific Heat ◽  
Supersonic Nozzle ◽  
Two Dimensional ◽  
Nozzle Design ◽  
Scheme Design ◽  
Specific Heat Ratio ◽  
Nozzle Contour ◽  
Ratio Change ◽  
Change Impact ◽  
The Impact

The practical requirements of the project the nozzle entrance temperature is high, the gas specific heat ratio varies greatly, so it must consider the specific heat ratio change impact on two-dimensional nozzle contour design. Divided into consideration specific heat ratio change and not consider two kinds of scheme design of 1.4Ma nozzle profile and build the model using the arc line method, numerical simulation is carried out through the CFD software Fluent, analysis of two kinds of design scheme comparison. The results show that, in the supersonic nozzle at low Maher numbers, two schemes of nozzle design profile similarity, parameters change little flow tube, export the Maher number and the flow quality can meet the design requirements, proof of specific heat ratio has little effect on the design results in the design of the nozzle under the condition of low Maher number.

An Analytical Study to Compare the Heat Transfer Performances of Water-Based TiO2, SiO2, TiC and SiC Nanofluids

2021 ◽  
Vol 408 ◽  
pp. 119-128
Author(s):  
Md Yeashir Arafat ◽  
Shashwata Chakraborty
Keyword(s):  
Heat Transfer ◽  
Thermophysical Properties ◽  
Figure Of Merit ◽  
Analytical Study ◽  
Convection Heat Transfer ◽  
Effective Density ◽  
Dispersion Effects ◽  
Water Based ◽  
Laminar And Turbulent Flow ◽  
Transfer Properties

The thermophysical properties as well as the thermal performance of a nanofluid can be altered upon varying the nanoparticle type and/or nanoparticle volume concentration. Herein, the effects of variable nanoparticle concentration on water-based TiO2, SiO2, TiC, and SiC nanofluids have been studied analytically. The dispersion effects of 1-4% nanoparticle on the single-phase forced convection heat transfer performance of the nanofluids have been investigated. The effective thermophysical properties of the nanofluids are determined adopting the general correlations. The flow velocities of the nanofluids relative to their base fluids are assumed to be constant. Mouromtseff number has been employed as a convenient figure of merit to compare the nanofluids under fully developed internal laminar and turbulent flow conditions. The results indicate an increase in effective density, thermal conductivity, and dynamic viscosity of the nanofluids. Nanofluids containing carbide suspensions exhibit superior heat transfer properties compared to those having oxide suspensions.

Figure of Merit-Based Optimization Approach of Phase Change Material-based Composites for Portable Electronics Using Simplified Model

2021 ◽  
Author(s):  
Ayushman Singh ◽  
Srikanth Rangarajan ◽  
Leila Choobineh ◽  
Bahgat Sammakia
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Material ◽  
Figure Of Merit ◽  
Volume Fraction ◽  
Simplified Model ◽  
Transient Temperature ◽  
Change Material

Abstract This work presents an approach to optimally designing a composite with thermal conductivity enhancers (TCEs) infiltrated with phase change material (PCM) based on figure of merit (FOM) for thermal management of portable electronic devices. The FOM defines the balance between effective thermal conductivity and energy storage capacity. In present study, TCEs are in the form of a honeycomb structure. TCEs are often used in conjunction with PCM to enhance the conductivity of the composite medium. Under constrained composite volume, the higher volume fraction of TCEs improves the effective thermal conductivity of the composite, while it reduces the amount of latent heat storage simultaneously. The present work arrives at the optimal design of composite for electronic cooling by maximizing the FOM to resolve the stated trade-off. In this study, the total volume of the composite and the interfacial heat transfer area between the PCM and TCE are constrained for all design points. A benchmarked two-dimensional direct CFD model was employed to investigate the thermal performance of the PCM and TCE composite. Furthermore, assuming conduction-dominated heat transfer in the composite, a simplified effective numerical model that solves the single energy equation with the effective properties of the PCM and TCE has been developed. The effective thermal conductivity of the composite is obtained by minimizing the error between the transient temperature gradient of direct and simplified model by iteratively varying the effective thermal conductivity. The FOM is maximized to find the optimal volume fraction for the present design.

scholarly journals Surface temperature and free-stream velocity oscillation effects on mixed convention slip flow from surface of a horizontal circular cylinder

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 13-23
Author(s):  
Zia Ullah ◽  
Muammad Ashraf ◽  
Saqib Zia ◽  
Ishtiaq Ali
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Mixed Convection ◽  
Surface Temperature ◽  
Skin Friction ◽  
Slip Velocity ◽  
Free Stream ◽  
Slip Flow ◽  
Stream Velocity ◽  
Velocity Oscillation

The present phenomena address the slip velocity effects on mixed convection flow of electrically conducting fluid with surface temperature and free stream velocity oscillation over a non-conducting horizontal cylinder. To remove the difficulties in illustrating the coupled PDE, the primitive variable formulation for finite dif?ference technique is proposed to transform dimensionless equations into primitive form. The numerical simulations of coupled non-dimensional equations are exam?ined in terms of fluid slip velocity, temperature, and magnetic velocity which are used to calculate the oscillating components of skin friction, heat transfer, and cur?rent density for various emerging parameters magnetic force parameter, ?, mixed convection parameter, ?, magnetic Prandtl number, ?, Prandtl number, and slip factor, SL. It is observed that the effect of slip flow on the non-conducting cylinder is reduced the fluid motion. A minimum oscillating behavior is noted in skin friction at each position but maximum amplitude of oscillation in heat transfer is observed at each position ? = ?/4 and 2?/3. It is further noticed that a fluid velocity increas?es sharply with the impact of slip factor on the fluid-flow mechanism. Moreover, due to frictional forces with lower magnitude between viscous layers, the rise in Prandtl number leads to decrease in skin fiction and heat transfer which is physi?cally in good agreement.

M10 Heat Transfer and Momentum Flux in Rarefied Gases

2010 ◽  
pp. 1375-1390 ◽  
Author(s):  
Arnold Frohn ◽  
Norbert Roth ◽  
Klaus Anders†
Keyword(s):  
Heat Transfer ◽  
Momentum Flux ◽  
Rarefied Gases

Prediction of Film Cooling Effectiveness and Heat Transfer due to Streamwise and Compound Angle Injection on Flat Surfaces

1995 ◽  
Author(s):  
S. Neelakantan ◽  
M. E. Crawford
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Momentum Flux ◽  
Flux Ratio ◽  
Equation Model ◽  
Transfer Coefficients ◽  
Film Cooling Effectiveness ◽  
Flat Surfaces ◽  
Momentum Flux Ratio ◽  
Density Ratios

The distributed Yavuzkurt injection model is extended to predict the effectiveness and heat transfer coefficients for film cooling injection from a single row of holes, aligned both along the direction of the freestream and at an angle with it. The injection angles were 24° and 35°. The compound angles considered were 50.5° and 60°. The Yavuzkurt film cooling model is used in conjunction with a one-equation model to yield the effectiveness and heat transfer predictions. The density ratios considered were 1.6 and 0.95 for the effectiveness predictions and 1.0 and 0.95 for the heat transfer predictions. For the effectiveness predictions, the blowing ratios range from 0.5 to 2.5, and the momentum flux ratios from 0.16 until 3.9. The hole spacings were 3, 6, and 7.8 hole diameters. The Yavuzkurt model constants are seen to be definitely correlated with the momentum flux ratio. Correlations for the model constants are obtained in terms of the momentum flux ratio. For the heat transfer predictions, the blowing ratios ranged from 0.4 to 2.0, and the momentum flux ratios from 0.16 to 3.9. The spacing between the holes was 3, 6, and 7.8 hole diameters. The matching between the effectiveness correlations and the heat transfer predictions is done on the basis of the momentum flux ratio. Results indicate that the Yavuzkurt model predictions are best for the in-line round holes. Heat transfer predictions are close to the experimental results for lower blowing ratios, until the ratio exceeds 1. For higher blowing ratios, the predictions, though less accurate, follow the experimental trends.

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