A Study of the Fabrication and Analysis of Micro Diffuser/Nozzles

2003 ◽  
Author(s):  
Kai-Shing Yang ◽  
Ing-Young Chen ◽  
Bor-Yuan Shew ◽  
Chi-Chuan Wang
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Pressure Loss ◽  
Measured Data ◽  
Loss Coefficient ◽  
Opening Angle ◽  
Velocity Change ◽  
Pressure Loss Coefficient ◽  
Micro Nozzle ◽  
Volumetric Flowrate

In this study, an analysis of the performance of micro nozzle/diffusers is performed and fabrication of the micro nozzle/diffuser is conducted and tested. It is found that the pressure loss coefficient for the nozzle/diffuser decreases with the Reynolds number. At a given Reynolds number, the pressure loss coefficient for nozzle is higher than that of the diffuser due to considerable difference in the momentum change. For the effect of nozzle/diffuser length on the pressure loss coefficient, it is found that the influence is rather small. At a fixed volumetric flowrate, a “minimum” phenomenon of the pressure loss coefficient vs. nozzle/diffuser depth is encountered. This is related to the interactions of velocity change and friction factor. Good agreements of the measured data with the predicted results are found in this study except at a diffuser having an opening angle of 20° . It is likely that the departure of this case to the prediction is due to the separation phenomenon in a larger angle of the diffuser.

Analysis of microdiffuser/nozzles

2006 ◽  
Vol 220 (8) ◽  
pp. 1289-1296 ◽  
Author(s):  
K-S Yang ◽  
M-S Liu ◽  
I-Y Chen ◽  
C-C Wang
Keyword(s):  
Reynolds Number ◽  
Flow Separation ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Side Wall ◽  
Loss Coefficient ◽  
Opening Angle ◽  
Three Dimensional Model ◽  
Velocity Change ◽  
Pressure Loss Coefficient

In this study, an analysis of the performance of micronozzle/diffusers is performed and fabrication of the micronozzle/diffuser is conducted and tested. It is found that the ratio of the loss coefficient of nozzle and diffuser increases with the Reynolds number and with the opening angle. At a given Reynolds number, the pressure loss coefficient for nozzle is higher than that of the diffuser due to considerable difference in the momentum change. At a fixed volumetric flowrate, a ‘minimum’ phenomenon of the pressure loss coefficient versus nozzle/diffuser depth is encountered. This is related to the interactions of velocity change and friction factor. Good agreements of the measured data with the predicted results are found in this study except at a diffuser having an opening angle of 20°. This is because of the presence of flow separation. The departure of this case to the prediction is due to the separation phenomenon in a larger angle of the diffuser. Hence, a more complicated two- and three-dimensional model is adopted to verify this flow separation inside the diffuser. For the simulation of the two-dimensional case, asymmetry flow field is seen for low Reynolds number region, whereas this phenomenon is not seen under three-dimensional simulation due to the confinement of the side wall.

Development of an Experimental Correlation for a Pressure Loss at a Side Orifice

2004 ◽  
Vol 127 (2) ◽  
pp. 388-392 ◽  
Author(s):  
Ho-Yun Nam ◽  
Jong-Man Kim ◽  
Kyung-Won Seo ◽  
Seok-Ki Choi
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Reynolds Numbers ◽  
Measured Data ◽  
Pressure Loss Coefficient ◽  
Liquid Metal Reactor ◽  
Experimental Correlation ◽  
Different Types ◽  
Reactor Fuel Assembly

An experimental study has been carried out to measure the pressure loss at the side orifice of a liquid metal reactor fuel assembly. The characteristics of the pressure loss at the side orifice are investigated using the experimental data measured from 17 different types of side orifices that have different geometric shapes, dimensions, and arrangements of nozzles, and a correlation that covers the whole flow range by one equation is developed. The error range of the correlation is within ±10%, and most of the errors occurred in a region where the Reynolds number is small. The range of Reynolds numbers based on the hydraulic diameter of the orifice is 2000–350,000. It is found that the geometric factor is the most important parameter for the pressure loss when the Reynolds number is >30,000. As the Reynolds number becomes smaller, its effect becomes larger, and when the Reynolds number is small, it is the most important parameter for the pressure loss at the side orifices. The measured data shows a trend that the pressure loss coefficient increases as the number of orifices increases, and the effect of the longitudinal arrangement is small.

Laminar Pressure Loss Coefficient in Close Coupled Fittings

2006 ◽  
Author(s):  
Murthy Lakshmiraju ◽  
Jie Cui
Keyword(s):  
Reynolds Number ◽  
Pressure Loss ◽  
Total Pressure ◽  
Laminar Flows ◽  
Loss Coefficient ◽  
Piping System ◽  
Duct System ◽  
Pressure Loss Coefficient ◽  
Intermediate Distance ◽  
Loss Coefficients

Close-coupled fittings are widely used in piping system to change the direction of the fluid and to connect pipes. These fittings cause losses and these losses play a significant role in the total pressure loss in a duct system. Numerical simulations were performed using Fluent on laminar flows in a circular pipe to obtain pressure loss coefficients associated with different fittings of two elbows and three elbows. Each configuration was studied with different intermediate distances between fittings of 0, 1, 3, 5, and 10 pipe diameters. It was observed that for a Reynolds number of 100 and for an intermediate distance less than 5 pipe diameters, the pressure loss coefficient for the coupled fittings was less than that of the uncoupled fittings. While the fittings become uncoupled when the intermediate distance was greater than 5 pipe diameters. Variation of velocity along the axis of the pipe was analyzed to understand the mechanism of the pressure loss for various fitting configurations with different intermediate distances.

Simulation of Compressible and Incompressible Flows Through Planar and Axisymmetric Abrupt Expansions

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Ali Nouri-Borujerdi ◽  
Ardalan Shafiei Ghazani
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Pressure Loss ◽  
Incompressible Flows ◽  
Splitting Method ◽  
Expansion Ratio ◽  
Loss Coefficient ◽  
Turbulent Regime ◽  
Reattachment Length ◽  
Pressure Loss Coefficient

In this paper, compressible and incompressible flows through planar and axisymmetric sudden expansion channels are investigated numerically. Both laminar and turbulent flows are taken into consideration. Proper preconditioning in conjunction with a second-order accurate advection upstream splitting method (AUSM+-up) is employed. General equations for the loss coefficient and pressure ratio as a function of expansion ratio, Reynolds number, and the inlet Mach number are obtained. It is found that the reattachment length increases by increasing the Reynolds number. Changing the flow regime to turbulent results in a decreased reattachment length. Reattachment length increases slightly with a further increase in Reynolds number. At a given inlet Mach number, the maximum value of the ratio of the reattachment length to step height occurs at the expansion ratio of about two. Moreover, the pressure loss coefficient is a monotonic increasing function of expansion ratio and increases drastically by increasing Mach number. Increasing inlet Mach number from 0.1 to 0.2 results in an increase in pressure loss coefficient by less than 5%. However, increasing inlet Mach number from 0.4 to 0.6 results in an increase in loss coefficient by 70–100%, depending on the expansion ratio. It is revealed that increasing Reynolds number beyond a critical value results in the loss of symmetry for planar expansions. Critical Reynolds numbers change adversely to expansion ratio. The flow regains symmetry when the flow becomes turbulent. Similar bifurcating phenomena are observed beyond a certain Reynolds number in the turbulent regime.

Frictional Flow Properties of Coal-Oil Slurries at Low Reynolds Number

1986 ◽  
Vol 108 (3) ◽  
pp. 211-213
Author(s):  
E. W. Beans ◽  
K. C. Masiulaniec
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Friction Factor ◽  
Particle Distribution ◽  
Reynolds Numbers ◽  
Loss Coefficient ◽  
Flow Properties ◽  
Pressure Loss Coefficient ◽  
Mass Fractions ◽  
Established Relationship

The pipe friction factor (f) and the pressure loss coefficient for a 90-deg EL (K90) were measured for coal-oil slurries at Reynolds numbers less than 100. A range of mass fractions (0 to 0.4) was examined for a single particle distribution. The pipe friction factor correlated well with the established relationship for laminar flow (f = 64/ReD) where Reynolds number is based on slurry properties. The loss coefficient for the elbow has a similar correlation.

Pressure-Loss Coefficient of 90 deg Sharp-Angled Miter Elbows

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Wameedh T. M. Al-Tameemi ◽  
Pierre Ricco
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Pressure Loss ◽  
Dynamic Pressure ◽  
Reynolds Numbers ◽  
Loss Coefficient ◽  
Straight Pipe ◽  
Pressure Loss Coefficient ◽  
Circular Pipes ◽  
Piping Systems

The pressure drop across 90deg sharp-angled miter elbows connecting straight circular pipes is studied in a bespoke experimental facility by using water and air as working fluids flowing in the range of bulk Reynolds number 500<Re<60,000. To the best of our knowledge, the dependence on the Reynolds number of the pressure drop across the miter elbow scaled by the dynamic pressure, i.e., the pressure-loss coefficient K, is reported herein for the first time. The coefficient is shown to decrease sharply with the Reynolds number up to about Re=20,000 and, at higher Reynolds numbers, to approach mildly a constant K=0.9, which is about 20% lower than the currently reported value in the literature. We quantify this relation and the dependence between K and the straight-pipe friction factor at the same Reynolds number through two new empirical correlations, which will be useful for the design of piping systems fitted with these sharp elbows. The pressure drop is also expressed in terms of the scaled equivalent length, i.e., the length of a straight pipe that would produce the same pressure drop as the elbow at the same Reynolds number.

Fabrication and Investigation of Curved PDMS Micro Nozzle/Diffuser

2008 ◽  
Vol 594 ◽  
pp. 357-362
Author(s):  
Yu Tang Chen ◽  
Chin Chun Hsu ◽  
Shung Wen Kang ◽  
Lung Chi Wu
Keyword(s):  
Reynolds Number ◽  
Pressure Loss ◽  
Analytic Solution ◽  
Numerical Data ◽  
Analysis And Design ◽  
Pressure Loss Coefficient ◽  
Micro Nozzle ◽  
Low Temperature Bonding ◽  
Bonding Technique ◽  
Good Agreement

This study describes the results on the fabrication, testing and analysis of curved micro nozzle/diffuser. First, we use different polymers, SU-8 and polydimethylsiloxane (PDMS) for the fabrication of curved micro nozzle/diffuser. By using the low-temperature bonding technique, we can combine the structure with the glass and accomplish the component. In order to understand the investigation and analysis of fluid dynamics characteristics, we measure the pressure and flow of curved micro nozzle/diffuser and the commercially available software CFD was adopted for analyzing the performance of straight and curved micro nozzle/ diffuser. If we have a given Reynolds number, the experimental data shows the pressure loss of the diffuser is lower than that of the nozzle due to the change of momentum. Furthermore, the results also indicate that the pressure loss coefficient of both curved nozzle and diffuser decrease with the Reynolds number. All the experimental and numerical data Eventually are compared with each other. The numerical data was found good agreement with previous analytic solution and experimental results. In sum, the theoretical analysis and design basis from this study can be formulated as the reference in the fabrication of micro nozzle/diffuser.

Pressure Loss Coefficient of Impingement Cooled Leading Edge System of a Turbine Blade

1976 ◽  
Vol 98 (4) ◽  
pp. 554-556
Author(s):  
D. K. Mukherjee
Keyword(s):  
Reynolds Number ◽  
Turbine Blade ◽  
Model Test ◽  
Pressure Loss ◽  
Leading Edge ◽  
Loss Coefficient ◽  
Relative Distance ◽  
Pressure Loss Coefficient

The pressure loss coefficient of an impingement cooled system similar to that often used to cool the leading edge of a turbine blade has been determined from model test. The influence of Reynolds number in the range tested is negligible. However, the influence of relative distance of the jet holes from the surface to be cooled is very significant.

Vibration suppression investigation and parametric design of tri-axle straight heavy truck with pitch-resistant hydraulically interconnected suspension

2021 ◽  
pp. 107754632110396
Author(s):  
Fei Ding ◽  
Jie Liu ◽  
Chao Jiang ◽  
Haiping Du ◽  
Jiaxi Zhou ◽  
...  
Keyword(s):  
Surface Area ◽  
Dynamic Load ◽  
Pressure Loss ◽  
Vibration Suppression ◽  
Parametric Design ◽  
Suspension System ◽  
Loss Coefficient ◽  
The Body ◽  
Impedance Matrix ◽  
Pressure Loss Coefficient

The vibration suppression of the proposed pitch-resistant hydraulically interconnected suspension system for the tri-axle straight truck is investigated, and the vibration isolation performances are parametrically designed to achieve smaller body vibration and tire dynamic load using increased pitch stiffness and optimized pressure loss coefficient. For the hydraulic subsystem, the transfer impedance matrix method is applied to derive the impedance matrix. These hydraulic forces are incorporated into the motion equations of mechanical subsystem as external forces according to relationships between boundary flow and mechanical state vectors. In terms of the additional mode stiffness/damping and suspension performance requirements, the cylinder surface area, accumulator pressure, and damper valve’s pressure loss coefficient are comprehensively tuned with parametric design technique and modal analysis method. It is found the isolation capacity is heavily dependent on installation scheme and fluid physical parameters. Especially, the surface area can be designed for the oppositional installation to separately raise pitch stiffness without increasing bounce stiffness. The pressure loss coefficients are tuned with design of experiment approach and evaluated using all conflict indexes with normalized dimensionless evaluation factors. The obtained numerical results indicate that the proposed pitch-resistant hydraulically interconnected suspension system can significantly inhibit both the body and tire vibrations with decreased suspension deformation, and the tire dynamic load distribution among wheel stations is also improved.

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