Effects of wall roughness on pressure loss and velocity distribution for air in fixed and moving granular layers

1972 ◽  
Vol 22 (1) ◽  
pp. 76-82
Author(s):  
V. K. Durnov ◽  
V. N. Timofeev
Keyword(s):  
Velocity Distribution ◽  
Pressure Loss ◽  
Wall Roughness ◽  
Granular Layers

A Study of Velocity Distribution Impact of Wall Roughness on Ultrasonic Gas Flowmeter

2012 ◽  
Vol 433-440 ◽  
pp. 349-352
Author(s):  
Feng Tang ◽  
Yue Zhong Li ◽  
Xiao Ming Guan
Keyword(s):  
Velocity Distribution ◽  
Velocity Vector ◽  
Gas Flow ◽  
Measuring Method ◽  
Time Interval ◽  
Wall Roughness ◽  
Flow Meter ◽  
Developed Turbulence ◽  
Flow Loss ◽  
Ultrasonic Flow Meter

In order to study the effects of velocity distribution of ultrasonic gas flow meter based on wall roughness, , a full developed turbulence model is established based on the theory of prandtl mixing length and flow loss coefficent λ has been calculated by using Colebrook friction correlation formula after analyzing time interval difference measuring method of ultrasonic flow meter. Through Matlab calculating and simulating velocity distribution in different conditions of wall roughness about the model shows and through Fluent simulating, velocity vector and pressure distribution in smooth and rough tube have been compared and analyzed. The experimental results shows that quantification of velocity distribution based on wall roughness can been solved with the model, and the analysis results have certain instructive significance to the development of ultrasonic gas flow meter.

scholarly journals Development of a Regenerator for an Automotive Gas Turbine Engine

1992 ◽  
Author(s):  
Junichi Sayama ◽  
Teru Morishita
Keyword(s):  
Velocity Distribution ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Prediction Method ◽  
Gas Turbine Engine ◽  
Core Size ◽  
Turbine Engine ◽  
Pressure Losses ◽  
The Core ◽  
Core Matrix

It is vital to accurately estimate the temperature effectiveness and pressure loss of the regenerator when designing a gas turbine engine because these characteristics basically determine the size, weight, and fuel consumption of the regenerative gas turbine engine. In operation of an actual engine, regenerators often fail to attain the characteristics predicted by conventional methods, because there are many performance-reducing irregularities such as the non-uniform velocity distribution of gases flowing into the core. In this paper, a prediction method that is based on data from actual engine tests is examined as a way to predict regenerator temperature effectiveness and pressure losses when there are causes for deterioration of these characteristics. This method resulted in a system, taking the deterioration of these characteristics into consideration as they occur in an actual engine, that represents temperature effectiveness and pressure loss as the function of core specifications such as the core size and the core matrix. This prediction method was then used to predict the regenerator characteristics of actual engines with more than satisfactory results (The accuracy is ±1.25% for temperature effectiveness and ±4% for pressure loss).

Development of a Regenerator for an Automotive Gas Turbine Engine

1993 ◽  
Vol 115 (2) ◽  
pp. 424-431 ◽  
Author(s):  
J. Sayama ◽  
T. Morishita
Keyword(s):  
Velocity Distribution ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Prediction Method ◽  
Gas Turbine Engine ◽  
Core Size ◽  
Turbine Engine ◽  
Pressure Losses ◽  
The Core ◽  
Core Matrix

It is vital to estimate the temperature effectiveness and pressure loss of the regenerator accurately when designing a gas turbine engine because these characteristics basically determine the size, weight, and fuel consumption of the regenerative gas turbine engine. In operation of an actual engine, regenerators often fail to attain the characteristics predicted by conventional methods, because there are many performance-reducing irregularities such as the nonuniform velocity distribution of gases flowing into the core. In this paper, a prediction method that is based on data from actual engine tests is examined as a way to predict regenerator temperature effectiveness and pressure losses when there are causes for deterioration of these characteristics. This method resulted in a system, taking the deterioration of these characteristics into consideration as they occur in an actual engine, that represents temperature effectiveness and pressure loss as the function of core specifications such as the core size and the core matrix. This prediction method was then used to predict the regenerator characteristics of actual engines with more than satisfactory results (the accuracy is ±1.25 percent for temperature effectiveness and ±4 percent for pressure loss).

Dynamics of comets in the collapsing protosolar nebula

1999 ◽  
Vol 173 ◽  
pp. 45-50
Author(s):  
L. Neslušan
Keyword(s):  
Solar System ◽  
Velocity Distribution ◽  
Oort Cloud ◽  
Interstellar Clouds ◽  
Protosolar Nebula ◽  
Moving Bodies

AbstractComets are created in the cool, dense regions of interstellar clouds. These macroscopic bodies take place in the collapse of protostar cloud as mechanically moving bodies in contrast to the gas and miscroscopic dust holding the laws of hydrodynamics. In the presented contribution, there is given an evidence concerning the Solar system comets: if the velocity distribution of comets before the collapse was similar to that in the Oort cloud at the present, then the comets remained at large cloud-centric distances. Hence, the comets in the solar Oort cloud represent a relict of the nebular stage of the Solar system.

VELOCITY DISTRIBUTION EFFECTS IN AIR FILTER TESTING

2001 ◽  
Vol 19 (1) ◽  
pp. 1-21 ◽  
Author(s):  
FRANK CHAMBERS ◽  
ABDEL AL-SARKHI ◽  
SHENGHONG YAO
Keyword(s):  
Velocity Distribution ◽  
Air Filter

Review on the aerodynamics of intermediate compressor duct

2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni
Keyword(s):  
High Pressure ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Outer Wall ◽  
Optimization Techniques ◽  
Optimum Pressure ◽  
Research Areas ◽  
Static Pressure Distribution ◽  
High Pressure Compressor ◽  
Pressure Compressor

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.

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