scholarly journals Design and Simulation of Radial Flow Turbine Impeller and Investigation Thermodynamic Properties of Flow in LE and TE

TEM Journal ◽  
2021 ◽  
pp. 975-980
Author(s):  
Kiumars Khani Aminjan ◽  
Milad Heidari ◽  
Pooyan Rahmanivahid ◽  
Houman Alipour ◽  
Morteza Khashehchi
Keyword(s):  
Power Generation ◽  
Thermodynamic Properties ◽  
Rotational Speed ◽  
Radial Flow ◽  
Leading Edge ◽  
Blade Surface ◽  
Design Data ◽  
Valid Data ◽  
Regular Path ◽  
Turbine Impeller

Centrifugal (radial flow) turbines are widely used in various industries, including power generation industries, so the study on them is of particular importance. The aim of this study was to investigate the thermodynamic properties of fluid flow in Trailing Edge (TE) and (LE) Leading Edge. For this purpose, first, the rotor (impeller) of the radial flow turbine was designed based on some design data such as flow rate, number of blades, rotational speed, diameter and length of the impeller, and then the designed rotor was simulated in 3D. The simulation done in the pressure based method and the turbulence model is SST and the rotational speed was 140,000(RPM). The results showed that the pressure, temperature and enthalpy in TE are less than LE and the areas close to the hub have the highest pressure. Another phenomenon observed is that in the section LE we see the separation of the flow from the blade surface, which then approaches the blade surface again and follows a relatively regular path,so the entropy in TE is greater than LE. At the end, the results of numerical solution were compared with valid data and the error rate and its reasons were discussed.

scholarly journals Aerothermal Investigations of Mixing Flow Phenomena in Case of Radially Inclined Ejection Holes at the Leading Edge

1999 ◽  
Author(s):  
Dieter E. Bohn ◽  
Karsten A. Kusterer
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Gas Turbines ◽  
Leading Edge ◽  
Suction Side ◽  
Pressure Side ◽  
Blade Surface ◽  
Cooling Fluid ◽  
Flow Phenomena ◽  
Vortex Systems

A leading edge cooling configuration is investigated numerically by application of a 3-D conjugate fluid flow and heat transfer solver, CHT-Flow. The code has been developed at the Institute of Steam and Gas Turbines, Aachen University of Technology. It works on the basis of an implicit finite volume method combined with a multi-block technique. The cooling configuration is an axial turbine blade cascade with leading edge ejection through two rows of cooling holes. The rows are located in the vicinity of the stagnation line, one row is on the suction side, the other row is on the pressure side. The cooling holes have a radial ejection angle of 45°. This configuration has been investigated experimentally by other authors and the results have been documented as a test case for numerical calculations of ejection flow phenomena. The numerical domain includes the internal cooling fluid supply, the radially inclined holes and the complete external flow field of the turbine vane in a high resolution grid. Periodic boundary conditions have been used in the radial direction. Thus, end wall effects have been excluded. The numerical investigations focus on the aerothermal mixing process in the cooling jets and the impact on the temperature distribution on the blade surface. The radial ejection angles lead to a fully three dimensional and asymmetric jet flow field. Within a secondary flow analysis it can be shown that complex vortex systems are formed in the ejection holes and in the cooling fluid jets. The secondary flow fields include asymmetric kidney vortex systems with one dominating vortex on the back side of the jets. The numerical and experimental data show a good agreement concerning the vortex development. The phenomena on the suction side and the pressure side are principally the same. It can be found that the jets are barely touching the blade surface as the dominating vortex transports hot gas under the jets. Thus, the cooling efficiency is reduced.

Film Cooling Effectiveness on the Leading Edge Region of a Rotating Turbine Blade With Two Rows of Film Cooling Holes Using Pressure Sensitive Paint

2006 ◽  
Vol 128 (9) ◽  
pp. 879-888 ◽  
Author(s):  
Jaeyong Ahn ◽  
M. T. Schobeiri ◽  
Je-Chin Han ◽  
Hee-Koo Moon
Keyword(s):  
Rotational Speed ◽  
Film Cooling ◽  
Rotor Blade ◽  
Incidence Angle ◽  
Leading Edge ◽  
Edge Region ◽  
Pressure Sensitive Paint ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Pressure Sensitive

Detailed film cooling effectiveness distributions are measured on the leading edge of a rotating gas turbine blade with two rows (pressure-side row and suction-side row from the stagnation line) of holes aligned to the radial axis using the pressure sensitive paint (PSP) technique. Film cooling effectiveness distributions are obtained by comparing the difference of the measured oxygen concentration distributions with air and nitrogen as film cooling gas respectively and by applying the mass transfer analogy. Measurements are conducted on the first-stage rotor blade of a three-stage axial turbine at 2400rpm (positive off-design), 2550rpm (design), and 3000rpm (negative off-design), respectively. The effect of three blowing ratios is also studied. The blade Reynolds number based on the axial chord length and the exit velocity is 200,000 and the total to exit pressure ratio was 1.12 for the first-stage rotor blade. The corresponding rotor blade inlet and outlet Mach numbers are 0.1 and 0.3, respectively. The film cooling effectiveness distributions are presented along with discussions on the influence of rotational speed (off design incidence angle), blowing ratio, and upstream nozzle wakes around the leading edge region. Results show that rotation has a significant impact on the leading edge film cooling distributions with the average film cooling effectiveness in the leading edge region decreasing with an increase in the rotational speed (negative incidence angle).

Cooling of Turbine Blades With Expanded Exit Holes: Computational Analyses of Leading Edge and Pressure-Side of a Turbine Blade

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Fariborz Forghan ◽  
Omid Askari ◽  
Uichiro Narusawa ◽  
Hameed Metghalchi
Keyword(s):  
High Speed ◽  
Turbine Blades ◽  
Leading Edge ◽  
Weak Shock ◽  
Suction Side ◽  
Pressure Side ◽  
Blade Surface ◽  
Cooling Effectiveness ◽  
Hot Gas ◽  
Computational Analyses

Turbine blades are cooled by a jet flow from expanded exit holes (EEH) forming a low-temperature film over the blade surface. Subsequent to our report on the suction-side (low-pressure, high-speed region), computational analyses are performed to examine the cooling effectiveness of the flow from EEH located at the leading edge as well as at the pressure-side (high-pressure, low-speed region). Unlike the case of the suction-side, the flow through EEH on the pressure-side is either subsonic or transonic with a weak shock front. The cooling effectiveness, η (defined as the temperature difference between the hot gas and the blade surface as a fraction of that between the hot gas and the cooling jet), is higher than the suction-side along the surface near the exit of EEH. However, its magnitude declines sharply with an increase in the distance from EEH. Significant effects on the magnitude of η are observed and discussed in detail of (1) the coolant mass flow rate (0.001, 0.002, and 0.004 (kg/s)), (2) EEH configurations at the leading edge (vertical EEH at the stagnation point, 50 deg into the leading-edge suction-side, and 50 deg into the leading-edge pressure-side), (3) EEH configurations in the midregion of the pressure-side (90 deg (perpendicular to the mainstream flow), 30 deg EEH tilt toward upstream, and 30 deg tilt toward downstream), and (4) the inclination angle of EEH.

Identification of Critical Net Positive Suction Head From Noise and Vibration in a Radial Flow Pump for Different Leading Edge Profiles of the Vane

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
S. Christopher ◽  
S. Kumaraswamy
Keyword(s):  
Radial Flow ◽  
Leading Edge ◽  
Open Circuit ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Noise And Vibration ◽  
Operating Condition ◽  
Radial Flow Pump ◽  
Flow Pump

Experimental investigations concerning cavitation in radial flow pump for three different leading edge profiles of the vane were carried out in an open circuit system. The operating condition of the radial flow pump under cavitating case was understood by measurement of noise and vibration along with the pump parameters for various speeds and flow rates. The outcome of the experimental results revealed that the noise and vibration were better predictors of inception and development of cavitation. Further observation inferred from critical net positive suction head (NPSH) curve of 3% head drop and critical NPSH value of noise and vibration are presented.

Numerical Investigations on the Power Generation of Turbo-Expander During the Propane De-Hydrogenation Process

2019 ◽  
Author(s):  
Hwabhin Kwon ◽  
Heesung Park
Keyword(s):  
Power Generation ◽  
Rotational Speed ◽  
Mechanical Energy ◽  
Pressure Ratio ◽  
Electrical Power ◽  
Operating Conditions ◽  
Hydrogenation Process ◽  
Operation Conditions ◽  
Turbo Expander ◽  
Discharge Pressure

Abstract A turboexpander for the propane de-hydrogenation process with blade and splitter has been numerically investigated. Since the turboexpander expands fluid from higher inlet pressure to lower discharge pressure, the kinetic energy of fluid is converted into useful mechanical energy. The efficiency and power generation with the designed turboexpander have been simulated with different operating conditions. The pressure ratio between inlet and outlet and rotational speed are varied to characterize the performance of the turboexpander as an electrical power generator. The numerical simulations have shown the vortex at the trailing edges of blade and splitter which decreases the efficiency. The rotational speed and the pressure ratio are parameterized to obtain operation conditions which achieve high power generation and efficiency. Consequently, the generated power from 614.12 kW to 693.45kW is obtained at the normal rotational speed and the pressure ratio between 1.75 to 2.22.

Numerical Simulation of Cavitating Flow in Mixed Flow Pump With Closed Type Impeller

2009 ◽  
Author(s):  
Katsutoshi Kobayashi ◽  
Yoshimasa Chiba
Keyword(s):  
Leading Edge ◽  
Suction Side ◽  
Experimental Results ◽  
Absolute Pressure ◽  
Pressure Side ◽  
Blade Surface ◽  
Mixed Flow ◽  
Closed Type ◽  
The Absolute ◽  
Flow Pump

LES (Large Eddy Simulation) with a cavitation model was performed to calculate an unsteady flow for a mixed flow pump with a closed type impeller. First, the comparison between the numerical and experimental results was done to evaluate a computational accuracy. Second, the torque acting on the blade was calculated by simulation to investigate how the cavitation caused the fluctuation of torque. The absolute pressure around the leading edge on the suction side of blade surface had positive impulsive peaks in both the numerical and experimental results. The simulation showed that those peaks were caused by the cavitaion which contracted and vanished around the leading edge. The absolute pressure was predicted by simulation with −10% error. The absolute pressure around the trailing edge on the suction side of blade surface had no impulsive peaks in both the numerical and experimental results, because the absolute pressure was 100 times higher than the saturated vapor pressure. The simulation results showed that the cavitation was generated around the throat, then contracted and finally vanished. The simulated pump had five throats and cavitation behaviors such as contraction and vanishing around five throats were different from each other. For instance, the cavitations around those five throats were not vanished at the same time. When the cavitation was contracted and finally vanished, the absolute pressure on the blade surface was increased. When the cavitation was contracted around the throat located on the pressure side of blade surface, the pressure became high on the pressure side of blade surface. It caused the 1.4 times higher impulsive peak in the torque than the averaged value. On the other hand, when the cavitation was contracted around the throat located on the suction side of blade surface, the pressure became high on the suction side of blade surface. It caused the 0.4 times lower impulsive peak in the torque than the averaged value. The cavitation around the throat caused the large fluctuation in torque acting on the blade.

scholarly journals Hastelloy® N for Molten Salt Reactors Used for Power Generation

2014 ◽  
Author(s):  
Robert W. Swindeman ◽  
Weiju Ren ◽  
Michael Katcher ◽  
David E. Holcomb
Keyword(s):  
Power Generation ◽  
Molten Salt ◽  
National Laboratory ◽  
Design Data ◽  
Creep Properties ◽  
Materials Properties ◽  
Oak Ridge ◽  
Case Development ◽  
Data Requirements ◽  
Nuclear Applications

Hastelloy® N alloy was developed in the 1950’s as ‘INOR 8’ by the Oak Ridge National Laboratory to resist molten salts used as a fuel and coolant in the early development of molten salt nuclear reactors for propulsion and power generation. China has recently expressed interest in Hastelloy N for use in prototype and demonstration components for a high-temperature, uranium-fueled, molten-salt cooled reactor for the production of electricity. An ASME Section III NH Code Case will be necessary to move Alloy N forward commercially. This paper discusses the guidelines for design data requirements necessary to satisfy the Boiler Code for elevated temperature nuclear applications where creep effects are significant. The historic tensile and creep properties data for Alloy N (N10003) were collected and re-analyzed in accordance with current ASME procedures. The collected data will be uploaded into the ASME Materials Properties Database to support the NH Code Case development. Paper published with permission.

A Comparison of Rotational Speed of Marine Current Power-Generation Turbine with and without a Speeding-up Inlet

2011 ◽  
Vol 383-390 ◽  
pp. 4516-4520 ◽  
Author(s):  
Zhi Yong Dong ◽  
Xu Zhang ◽  
Li Wang ◽  
Wei Han ◽  
Xiao Wei Yu ◽  
...  
Keyword(s):  
Power Generation ◽  
Flow Velocity ◽  
Rotational Speed ◽  
Free Stream ◽  
Marine Current ◽  
Presence And Absence ◽  
Current Energy

This paper experimentally investigates effects of speeding-up inlet on rotational speed of marine current energy turbine. Several length-radius ratios L/d and area ratios A´/A of the speeding-up inlet as well as several flow yawing angles θ were considered. Also, a comparison of rotational speed of turbine in the presence and absence of speeding-up inlet was made. A relation between flow velocity V and rotational speed of the inlet n was analyzed. And a relation between flow velocity and rotational speed of turbine in free stream was theoretically developed.

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