scholarly journals Discharge Coefficients of a Heavy Suspension Nozzle

2021 ◽  
Vol 11 (6) ◽  
pp. 2619
Author(s):  
Carlos Rio-Cano ◽  
Navid M. Tousi ◽  
Josep M. Bergada ◽  
Angel Comas
Keyword(s):  
Flow Direction ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Pressure Ratio ◽  
Working Fluid ◽  
Heavy Vehicles ◽  
Vehicle Suspensions ◽  
Discharge Coefficients ◽  
Nozzle Configuration ◽  
Real Flow

The suspensions used in heavy vehicles often consist of several oil and two gas chambers. In order to perform an analytical study of the mass flow transferred between two gas chambers separated by a nozzle, and when considering the gas as compressible and real, it is usually needed to determine the discharge coefficient of the nozzle. The nozzle configuration analyzed in the present study consists of a T shape, and it is used to separate two nitrogen chambers employed in heavy vehicle suspensions. In the present study, under compressible dynamic real flow conditions and at operating pressures, discharge coefficients were determined based on experimental data. A test rig was constructed for this purpose, and air was used as working fluid. The study clarifies that discharge coefficients for the T shape nozzle studied not only depend on the pressure gradient between chambers but also on the flow direction. Computational Fluid Dynamic (CFD) simulations, using air as working fluid and when flowing in both nozzle directions, were undertaken, as well, and the fluid was considered as compressible and ideal. The CFD results deeply helped in understanding why the dynamic discharge coefficients were dependent on both the pressure ratio and flow direction, clarifying at which nozzle location, and for how long, chocked flow was to be expected. Experimentally-based results were compared with the CFD ones, validating both the experimental procedure and numerical methodologies presented. The information gathered in the present study is aimed to be used to mathematically characterize the dynamic performance of a real suspension.

CFD Assessment and Experimental Investigation of the Liquid Separation Efficiency Enhancements in a Vertical Gravity Separator

2020 ◽  
Vol 28 (03) ◽  
pp. 2050021
Author(s):  
Raid Ahmed Mahmood
Keyword(s):  
Separation Efficiency ◽  
Flow Direction ◽  
Fluid Dynamic ◽  
Working Fluid ◽  
Cfd Simulations ◽  
Liquid Separation ◽  
Flash Tank ◽  
Tank Design ◽  
Vertical Gravity ◽  
Design Options

Three design enhancement options for a vertical gravitational flash tank separator were proposed and investigated in this work. Computational Fluid Dynamic (CFD) was used to assess the optimum configurations of the vertical gravitational flash tank separator. A series of experiments were performed to test the CFD proposed configurations of the enhancement design options. This paper also assessed the usefulness of CFD in flash tank design, and this is achieved through experiments and simulations on a range of relevant configurations using water as the working fluid. The results revealed that the combination of the inlet flow direction and extractor had a significant effect on the performance of the vertical flash tank separator which increased by 2%. The results also revealed that there was a good agreement between the CFD simulations and experiments; the CFD simulations underestimated the liquid separation efficiency by approximately 0.02 over the range of conditions tested.

Film Cooling Discharge Coefficient Measurements in a Turbulated Passage With Internal Crossflow

2001 ◽  
Vol 123 (4) ◽  
pp. 774-780 ◽  
Author(s):  
Ronald S. Bunker ◽  
Jeremy C. Bailey
Keyword(s):  
Film Cooling ◽  
Discharge Coefficient ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Substantial Effect ◽  
Internal Cooling ◽  
Gas Turbine Blades ◽  
Discharge Coefficients ◽  
Cooling Enhancement

Gas turbine blades utilize internal geometry such as turbulator ribs for improved cooling. In some designs it may be desirable to benefit from the internal cooling enhancement of ribs as well as external film cooling. An experimental study has been performed to investigate the effect of turbulator rib placement on film hole discharge coefficient. In the study, a square passage having a hydraulic diameter of 1.27 cm is used to feed a single angled film jet. The film hole angle to the surface is 30 deg and the hole length-to-diameter ratio is 4. Turbulators were placed in one of three positions: upstream of film hole inlet, downstream of film hole inlet, and with the film hole inlet centered between turbulators. For each case 90 deg turbulators with a passage blockage of 15 percent and a pitch to height ratio of 10 were used. Tests were run varying film hole-to-crossflow orientation as 30, 90, and 180 deg, pressure ratio from 1.02 to 1.8, and channel crossflow velocity from Mach 0 to 0.3. Film hole flow is captured in a static plenum with no external crossflow. Experimental results of film discharge coefficients for the turbulated cases and for a baseline smooth passage are presented. Alignment of the film hole entry with respect to the turbulator is shown to have a substantial effect on the resulting discharge coefficients. Depending on the relative alignment and flow direction discharge coefficients can be increased or decreased 5–20 percent from the nonturbulated case, and in the worst instance experience a decrease of as much as 50 percent.

Design of a Centrifugal Turbo Compressor With the Working Fluid Water for the Operation in a Hybrid Sorption/Compression Heat Pump Cycle

2016 ◽  
Author(s):  
Thomas Eckert ◽  
Leo Dostal ◽  
Martin Helm ◽  
Christian Schweigler
Keyword(s):  
Heat Pump ◽  
High Speed ◽  
Fluid Dynamic ◽  
Pressure Ratio ◽  
Lithium Bromide ◽  
High Volume ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Working Fluid ◽  
Turbo Compressor

In various applications the use of sorption chillers and heat pumps is limited by the available temperature level of the driving heat source or the heat sink for export of reject heat. These constraints can be overcome by integrating an efficient high-speed transonic turbo compressor into the internal cycle of a thermally driven water/lithium bromide absorption heat pump. The operation in a hybrid heat pump with the refrigerant water implies specific challenges for the design of the compressor: Saturation pressures in the sub-atmospheric range, low vapor density, high volume flows and a targeted pressure ratio of 3 result in high impeller tip speeds with machine Mach numbers close to 1. Here the authors present a theoretical design study based on a numerical simulation of a centrifugal compressor, targeted at the given operating conditions. Evaluation of the results is conducted with regard to the relevant thermodynamic and fluid mechanic figures. The optimization of the impeller geometry comprises both fluid dynamic behavior and structural stability.

Design of a Variable Geometry Axial-Inflow Turbine Turbocharger Equipped With a Diffuser-Collector System

2018 ◽  
Author(s):  
Apostolos Pesyridis ◽  
Alessandro Cappiello ◽  
Raffaele Tuccillo
Keyword(s):  
Radial Flow ◽  
Flow Direction ◽  
Fluid Dynamic ◽  
Pressure Ratio ◽  
Variable Geometry ◽  
Discharge System ◽  
Engine Torque ◽  
Collector System ◽  
Axial Turbines ◽  
Turbine Design

The fluid-dynamic design of a bespoke variable geometry axial inflow turbine, equipped with a diffuser-collector system for turbocharging applications, was numerically investigated with the purpose of replacing the radial flow turbine in a commercial turbocharger. The paper aims to investigate the suitability of axial turbines for turbocharging applications in the automotive field. The turbine outflow is linked to a diffuser-collector system in order to obtain a kinetic energy recovery together with a correct flow direction to the discharge system. Additionally, once completed the turbine design, the operating maps for three different stator positions were numerically obtained. Finally, a turbocharger–engine matching model allowed comparison of the new axial and conventional radial flow turbine in terms of turbine power and efficiency, compressor pressure ratio, engine torque and BSFC.

Film Cooling Discharge Coefficient Measurments in a Turbulated Passage With Internal Cross Flow

2001 ◽  
Author(s):  
Ronald S. Bunker ◽  
Jeremy C. Bailey
Keyword(s):  
Film Cooling ◽  
Discharge Coefficient ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Cross Flow ◽  
Substantial Effect ◽  
Internal Cooling ◽  
Discharge Coefficients ◽  
Cooling Enhancement

Gas turbine blades utilize internal geometry such as turbulator ribs for improved cooling. In some designs it may be desirable to benefit from the internal cooling enhancement of ribs as well as external film cooling. An experimental study has been performed to investigate the effect of turbulator rib placement on film hole discharge coefficient. In the study a square passage having a hydraulic diameter of 1.27 cm is used to feed a single angled film jet. The film hole angle to the surface is 30° and the hole length-to-diameter ratio is 4. Turbulators were placed in one of three positions: upstream of film hole inlet, downstream of film hole inlet, and with the film hole inlet centered between turbulators. For each case 90° turbulators with a passage blockage of 15% and a pitch to height ratio of 10 were used. Tests were run varying film hole-to-cross flow orientation as 30°, 90°, and 180°, pressure ratio from 1.02 to 1.8, and channel cross flow velocity from Mach 0 to 0.3. Film hole flow is captured in a static plenum with no external cross flow. Experimental results of film discharge coefficients for the turbulated cases and for a baseline smooth passage are presented. Alignment of the film hole entry with respect to the turbulator is shown to have a substantial effect on the resulting discharge coefficients. Depending on the relative alignment and flow direction, discharge coefficients can be increased or decreased 5 to 20% from the non-turbulated case, and in the worst instance experience a decrease of as much as 50%.

Effect of Internal Coolant Crossflow Orientation on the Discharge Coefficient of Shaped Film Cooling Holes

1999 ◽  
Author(s):  
Michael Gritsch ◽  
Christian Saumweber ◽  
Achmed Schulz ◽  
Sigmar Wittig ◽  
Edwin Sharp
Keyword(s):  
Mach Number ◽  
Film Cooling ◽  
Gas Flow ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Strong Impact ◽  
Hot Gas ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Cooling Hole

Discharge coefficients of three film-cooling hole geometries are presented over a wide range of engine like conditions. The hole geometries comprise a cylindrical hole and two holes with a diffuser shaped exit portion (a fanshaped and a laidback fanshaped hole). For all three hole geometries the hole axis was inclined 30° with respect to the direction of the external (hot gas) flow. The flow conditions considered were the hot gas crossflow Mach number (up to 0.6), the coolant crossflow Mach number (up to 0.6) and the pressure ratio across the hole (up to 2). The effect of internal crossflow approach direction, perpendicular or parallel to the main flow direction, is particularly addressed in the present study. Comparison is made of the results for a parallel and perpendicular orientation, showing that the coolant crossflow orientation has a strong impact on the discharge behavior of the different hole geometries. The discharge coefficients were found to strongly depend on both hole geometry and crossflow conditions. Furthermore, the effects of internal and external crossflow on the discharge coefficients were described by means of correlations used to derive a predicting scheme for discharge coefficients. A comparison between predictions and measurements reveals the capability of the method proposed.

scholarly journals Fully turbulent discrete adjoint solver for non-ideal compressible flow applications

2017 ◽  
Vol 1 ◽  
pp. Z1FVOI ◽  
Author(s):  
Salvatore Vitale ◽  
Tim A. Albring ◽  
Matteo Pini ◽  
Nicolas R. Gauger ◽  
Piero Colonna
Keyword(s):  
Oil And Gas ◽  
Automatic Differentiation ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Oil And Gas Industry ◽  
Ideal Gas ◽  
Working Fluid ◽  
Viscous Effects ◽  
Two Phase ◽  
Flow Equations

Abstract Non-Ideal Compressible Fluid-Dynamics (NICFD) has recently been established as a sector of fluid mechanics dealing with the flows of dense vapors, supercritical fluids, and two-phase fluids, whose properties significantly depart from those of the ideal gas. The flow through an Organic Rankine Cycle (ORC) turbine is an exemplary application, as stators often operate in the supersonic and transonic regime, and are affected by NICFD effects. Other applications are turbomachinery using supercritical CO2 as working fluid or other fluids typical of the oil and gas industry, and components of air conditioning and refrigeration systems. Due to the comparably lower level of experience in the design of this fluid machinery, and the lack of experimental information on NICFD flows, the design of the main components of these processes (i.e., turbomachinery and nozzles) may benefit from adjoint-based automated fluid-dynamic shape optimization. Hence, this work is related to the development and testing of a fully-turbulent adjoint method capable of treating NICFD flows. The method was implemented within the SU2 open-source software infrastructure. The adjoint solver was obtained by linearizing the discretized flow equations and the fluid thermodynamic models by means of advanced Automatic Differentiation (AD) techniques. The new adjoint solver was tested on exemplary turbomachinery cases. Results demonstrate the method effectiveness in improving simulated fluid-dynamic performance, and underline the importance of accurately modeling non-ideal thermodynamic and viscous effects when optimizing internal flows influenced by NICFD phenomena.

Effect of Internal Coolant Crossflow Orientation on the Discharge Coefficient of Shaped Film-Cooling Holes

1999 ◽  
Vol 122 (1) ◽  
pp. 146-152 ◽  
Author(s):  
M. Gritsch ◽  
C. Saumweber ◽  
A. Schulz ◽  
S. Wittig ◽  
E. Sharp
Keyword(s):  
Mach Number ◽  
Film Cooling ◽  
Gas Flow ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Strong Impact ◽  
Hot Gas ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Cooling Hole

Discharge coefficients of three film-cooling hole geometries are presented over a wide range of engine like conditions. The hole geometries comprise a cylindrical hole and two holes with a diffuser-shaped exit portion (a fanshaped and a laidback fanshaped hole). For all three hole geometries the hole axis was inclined 30 deg with respect to the direction of the external (hot gas) flow. The flow conditions considered were the hot gas crossflow Mach number (up to 0.6), the coolant crossflow Mach number (up to 0.6) and the pressure ratio across the hole (up to 2). The effect of internal crossflow approach direction, perpendicular or parallel to the main flow direction, is particularly addressed in the present study. Comparison is made of the results for a parallel and perpendicular orientation, showing that the coolant crossflow orientation has a strong impact on the discharge behavior of the different hole geometries. The discharge coefficients were found to strongly depend on both hole geometry and crossflow conditions. Furthermore, the effects of internal and external crossflow on the discharge coefficients were described by means of correlations used to derive a predicting scheme for discharge coefficients. A comparison between predictions and measurements reveals the capability of the method proposed. [S0889-504X(00)01601-9]

scholarly journals Large Eddy Simulations of Strongly Non-Ideal Compressible Flows through a Transonic Cascade

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 772
Author(s):  
Jean-Christophe Hoarau ◽  
Paola Cinnella ◽  
Xavier Gloerfelt
Keyword(s):  
Compressible Flows ◽  
Flow Behavior ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Large Eddy Simulations ◽  
Working Fluid ◽  
Viscous Effects ◽  
Large Eddy

Transonic flows of a molecularly complex organic fluid through a stator cascade were investigated by means of large eddy simulations (LESs). The selected configuration was considered as representative of the high-pressure stages of high-temperature Organic Rankine Cycle (ORC) axial turbines, which may exhibit significant non-ideal gas effects. A heavy fluorocarbon, perhydrophenanthrene (PP11), was selected as the working fluid to exacerbate deviations from the ideal flow behavior. The LESs were carried out at various operating conditions (pressure ratio and total conditions at inlet), and their influence on compressibility and viscous effects is discussed. The complex thermodynamic behavior of the fluid generates highly non-ideal shock systems at the blade trailing edge. These are shown to undergo complex interactions with the transitional viscous boundary layers and wakes, with an impact on the loss mechanisms and predicted loss coefficients compared to lower-fidelity models relying on the Reynolds-averaged Navier–Stokes (RANS) equations.

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

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