Impact of surface roughness on gas turbine engine fan and compressor rotor

Ashima Malhotra,Shraman Goswami,A. M. Pradeep 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

A gas turbine engine, being an open cycle engine, gets exposed to atmospheric conditions through the intake of air from the surroundings. Debris of different sizes comes into the engine through the fan inlet and impinges on the different components inside the engine, making them rough. Another source of roughness is encountered with the manufacturing process itself. Hence it is important to understand the impact of surface roughness on the performance of either an engine in the field or a newly designed engine. The current work focuses on the performance impact of surface roughness on a fan rotor and a compressor rotor. The flow field is numerically studied with and without roughness. The flow field of a fan rotor is generally different from a compressor rotor, specifically in terms of shock structure and secondary flow, and hence a comparative study is made to understand the impact of roughness in presence of different flow fields. The NASA rotor67 (fan rotor) and the NASA rotor37 (compressor rotor) are used for the numerical study carried out for this work. The results indicate that the extent of performance loss is more for compressor rotor (NASA rotor37) for same amount of roughness used on fan and compressor rotor. A detailed flow field investigation from the numerical study is presented to understand the reason behind the different extents of performance loss. It is found that not only the amount of roughness but also the flow field plays a significant role on the performance of a gas turbine engine fan and compressor rotor.

Early Growth Response of Broilers to Dietary Lysine at Fixed Ratio to Crude Protein and Essential Amino Acids

Panda, A.K.,Rao, S.V. Rama,Raju, M.V.L.N.,Lavanya, G.,Reddy, E. Pradeep Kumar,Sunder, G. Shyam Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.11

The effects of dietary lysine (Lys) at a fixed ratio to crude protein (CP) and essential amino acids (EAA) on early growth response of broilers were studied. Four diets were formulated to contain similar metabolizable energy (ME, 2,950 kcal/kg) but contained graded levels of incremental Lys (1.1, 1.2, 1.3 and 1.4%) while also increasing the dietary CP and EAA (methionine, methionine+ cystine, threonine and tryptophan) to maintain a constant ratio with Lys. Each diet was fed at random to 10 replicates of 6 chicks each throughout the experimental period (1-21 d). At the lowest concentration of Lys of 1.1% (19.04% CP), body weight gain (BWG) was lowest and feed conversion ratio (FCR) was poorest. The BWG increased and FCR decreased linearly as dietary Lys increased upto 1.3% (22.5% CP). Lowest feed consumption was observed in the dietary group that contained 1.1% Lys (19.04% CP) in the diet. Increasing the concentration of Lys to 1.2% (20.77% CP), significantly increased the feed consumption. The concentrations of protein, calcium, phosphorus and cholesterol in serum were not influenced by the variation in Lys contents in the diet. The humoral immune response as measured by antibody titre in response to SRBC inoculation was significantly lower in the diets containing 1.1% Lys compared to 1.4%. It is concluded that the Lys requirement of broilers is 1.3% (22.5% CP) during 0 to 21 days of age for eliciting optimum performance when a fixed ratio of Lys to CP (1:17.31) and essential AA is maintained (1:0.47 Met; 1:0.56 Thr; 1:0.17 Try).

Distribution of Serotypes and Antibiotic Susceptibility Patterns Among Invasive Pneumococcal Diseases in Saudi Arabia

Yazeed A. Al-Sherikh,Lakshmana K. Gowda,M. Marie Mohammed Ali,James John,Dabwan Khaled Homoud Mohammed,Pradeep Chikkabidare Shashidhar 대한진단검사의학회 2014 Annals of Laboratory Medicine Vol.34 No.3

Background: Streptococcus pneumoniae causes life-threatening infections such as men- ingitis, pneumonia, and febrile bacteremia, particularly in young children. The increasing number of drug-resistant isolates has highlighted the necessity for intervening and control- ling disease. To achieve this, information is needed on serotype distribution and patterns of antibiotic resistance in children. Methods: All cases of invasive pneumococcal disease (IPD) in children aged less than 15 yr recorded at King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia, were reviewed for serotyping and antibiotic susceptibility. Isolates were collected from 78 consecutive patients with IPD between 2009 and 2012. All collected isolates were sub- jected to serotyping by co-agglutination, sequential multiplex PCR, and single PCR se- quetyping as previously described. Results: The most frequently isolated IPD serotypes were 23F, 6B, 19F, 18C, 4, 14, and 19A, which are listed in decreasing order and cover 77% of total isolates. The serotype coverage for the pneumococcal conjugate vaccine (PCV)7, PCV10, and PCV13 was 77%, 81%, and 90%, respectively. Results from sequential multiplex PCR agreed with co-agglu- tination results. All serotypes could not be correctly identified using single PCR sequetyp- ing. Minimum inhibitory concentration showed that 50 (64%) isolates were susceptible to penicillin, whereas 70 (90%) isolates were susceptible to cefotaxime. Conclusions: The most common pneumococcal serotypes occur with frequencies similar to those found in countries where the PCV has been introduced. The most common sero- types in this study are included in the PCVs. Addition of 23A and 15 to the vaccine would improve the PCV performance in IPD prevention.

Analysis of micro and nano particle erosion by analytical, numerical and experimental methods: A review

Suhas M. Shinde,Dayanand M. Kawadekar,Pradeep A. Patil,Virendra K. Bhojwani 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.5

Erosion is one of the vital factors to consider for damage of solid-liquid, solid-gas multiphase flow system. The presence of solid particles in the fluid domain initiates the erosion. This paper focuses on the erosion analysis methods. Different erosion models for analytical and numerical investigation are discussed along with experimental test processes for erosion. Further, possible techniques used for analyzing the eroded surfaces are discussed. This study will be helpful for researchers working on erosion phenomena which can find erosion by analytical, numerical as well as experimental ways. Erosion prediction before implementation will save the system performance degradation. Lastly, consideration of the factors like temperature, impact angle variation during the flow and complex geometry is recommended for future study.

Distribution of Serotypes and Antibiotic Susceptibility Patterns Among Invasive Pneumococcal Diseases in Saudi Arabia

Yazeed A. Al-Sheikh,Lakshmana K. Gowda,M. Marie Mohammed Ali,James John,Dabwan Khaled Homoud Mohammed,Pradeep Chikkabidare Shashidhar 대한진단검사의학회 2014 Annals of Laboratory Medicine Vol.34 No.5

Background Streptococcus pneumoniae causes life-threatening infections such as meningitis, pneumonia, and febrile bacteremia, particularly in young children. The increasing number of drug-resistant isolates has highlighted the necessity for intervening and controlling disease. To achieve this, information is needed on serotype distribution and patterns of antibiotic resistance in children. Methods All cases of invasive pneumococcal disease (IPD) in children aged less than 15 yr recorded at King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia, were reviewed for serotyping and antibiotic susceptibility. Isolates were collected from 78 consecutive patients with IPD between 2009 and 2012. All collected isolates were subjected to serotyping by co-agglutination, sequential multiplex PCR, and single PCR sequetyping as previously described. Results The most frequently isolated IPD serotypes were 23F, 6B, 19F, 18C, 4, 14, and 19A, which are listed in decreasing order and cover 77% of total isolates. The serotype coverage for the pneumococcal conjugate vaccine (PCV)7, PCV10, and PCV13 was 77%, 81%, and 90%, respectively. Results from sequential multiplex PCR agreed with co-agglutination results. All serotypes could not be correctly identified using single PCR sequetyping. Minimum inhibitory concentration showed that 50 (64%) isolates were susceptible to penicillin, whereas 70 (90%) isolates were susceptible to cefotaxime. Conclusions The most common pneumococcal serotypes occur with frequencies similar to those found in countries where the PCV has been introduced. The most common serotypes in this study are included in the PCVs. Addition of 23A and 15 to the vaccine would improve the PCV performance in IPD prevention.

Microstructural analysis, radiography, tool wear characterization, induced residual stress and corrosion behavior of conventional and cryogenic trepanning of DSS 2507

C. Chandrasekhara Sastry,M. Abeens,N. Pradeep,M. A. Muthu Manickam 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

In the present study, an endeavour has been made in trepanning of Duplex steel (DSS 2507) under wet and cryogenic environments. DSS 2507 steel is predominantly used in the area of defence for warhead and rocket motor casing, marine applications of submarine rocket launchers, naval components and other high end applications due to their high strength provided by two phased structure. Reduction of 35.21 % and 14.80 % is observed in cryogenic trepanning correlated to conventional trepanning analogous to cutting force and cutting temperature, respectively. This has an explicit bearing on the machinability and surface characteristics of the hole formed. Attrition of immured austenite phase fraction and curtailed carbide structure aids to the increase in the residual (compressive in nature) stress by 3.25 % in cryogenic trepanning, further causing an accretion of wear resistance and hardness. An increase in work hardness and inherent machinability property is observed with a surge in microhardness by 11-26.07 %, due to the upsurge of ferrite band along the surface. Additionally, ferrite formation ensures abatement the formation of embedded chips along the surface in cryogenic trepanning. Increase in MRR is ascertained at 0.8 % in cryogenic trepanning compared to conventional trepanning. A decrease of 30.99 % and 72.30 % in flank and crater wear, respectively is ascertained in cryogenic trepanning in correlation to conventional trepanning of DSS 2507 steel is ascertained. The corrosion resistance in cryogenic trepanning increased by 59.78 % analogous to conventional trepanning of DSS 2507 steel. In cryogenic trepanning, a passivation barrier is ascertained with interatomic spacing curtailment along with a surge of ferrite phase, causing an upsurge in the compressive residual factor.

Replacement of Normal Maize with Quality Protein Maize on Performance, Immune Response and Carcass Characteristics of Broiler Chickens

Panda, A.K.,Raju, M.V.L.N.,Rao, S.V. Rama,Lavanya, G.,Reddy, E. Pradeep Kumar,Sunder, G. Shyam Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.12

An experiment was conducted to evaluate the effect of dietary replacement of normal maize (NM) with quality protein maize (QPM) on performance, immune response and carcass characteristics of broiler (Krishibro) chickens. Six experimental diets were prepared separately for starter and finisher phases. Diet 1 was a control diet formulated with NM and soybean meal. In diets 2-5, the NM was replaced with QPM at 25, 50, 75 and 100%, respectively. Diet 6 was the same as the control diet, but supplemented with synthetic lysine similar to the industry standard. Each test diet was fed to 8 replicates, each of 5 chicks, reared in stainless steel battery brooders. The AME content of QPM (3382 kcal/kg) was similar to that of NM (3,352 kcal/kg), but protein (9.91 vs. 8.94%), lysine (0.40 vs. 0.26%) and tryptophan (0.09 vs. 0.07%) contents of QPM were higher than NM. Dietary replacement of NM with 50% QPM significantly (p<0.05) improved body weight gain, feed conversion ratio, humoral immune response, relative bursa weight, and breast muscle yield and lowered abdominal fat content. No further improvement in these parameters was recorded by increasing the level of replacement of NM with QPM to either 75% or 100%. Further, the improvement noticed in the 50% QPM group was similar to the group fed the NM diet with lysine supplementation, and thus dietary replacement of NM with QPM at 50% did not need extra synthetic lysine supplementation. It is concluded that dietary replacement of NM with QPM at the 50% level resulted in optimum performance, higher breast muscle yield and higher immune response in broiler chickens.

Effect of Microstructure on the Environmentally Induced Cracking Behavior of Al-Zn-Mg-Cu-Zr Aluminum Alloy

( Rahul Ghosh ),( A. Venugopal ),( Pradeep P I ),( L. Rama Krishna ),( P. Ramesh Narayanan ),( Bhanu Pant ),( Roy M Cherian ) 한국부식방식학회(구 한국부식학회) 2018 Corrosion Science and Technology Vol.17 No.3

AA7010 is an Al-Zn-Mg-Cu alloy containing Zr, developed as an alternate to traditional AA7075 alloy owing to their high strength combined with better fracture toughness. It is necessary to improve the corrosion resistance and surface properties of the alloy by incorporating plasma electrolytic oxidation (PEO) method. AA7010-T7452 aluminum alloy has been processed through the forging route with multi-stage working operations, and was coated with 10μm thick Al₂O₃ ceramic aluminina coating using the plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviours were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. The results indicated that the additional thermomechanical treatment during the forging process caused a fully recrystallized microstructure, which lead to the poor environmental cracking resistance of the alloy in 3.5% NaCl solution, despite the overaging treatment. Although the fabricated PEO coating improved general corrosion resistance, the brittle nature of the coating did not provide any improvement in SCC resistance of the alloy. However, the hardness and elastic modulus of the coating were significantly higher than the base alloy.

Microstructure Characterization and Charpy Toughness of P91 Weldment for As-Welded, Post-Weld Heat Treatment and Normalizing & Tempering Heat Treatment

Chandan Pandey,M. M. Mahapatra,Pradeep Kumar,A. Giri 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.5

The effect of weld groove design and heat treatment on microstructure evolution and Charpy toughness of P91pipe weldments was studied. The P91 pipe weldments were subjected to subcritical post weld heat treatment(760 °C-2 h) and normalizing/tempering conditions (normalized-1040 °C/40 min, air cooled; tempered 760 °C/2 h,air cooled) were employed. The influence of subsequent PWHT and N&T treatment on the microstructure of variouszone of P91 pipe weldments were also investigated. The present investigation also described the effect ofPWHT and N&T treatment on hardness, grain size, precipitate size, inter-particle spacing and fraction area of precipitatespresent in each zone of P91 pipe weldments. The result indicated great impact of heat treatment on theCharpy toughness and microstructure evolution of P91 weldments. The N&T treatment was found to be moreeffective heat treatment compared to subsequent PWHT. Charpy toughness value was found to be higher for narrow-groove design as compared to conventional V-groove design.

Electrical and interface properties of PdAl/Au metal alloyed ohmic contacts on p-type GaN for high-temperature MEMS devices

Puneetha, P. T.,Reddy, M. S.,Lee, Y. W.,Jeong, S. H.,Lokanadham, R.,Park, C.,Pradeep, A. G.,Rajagopal Reddy, V. Springer Science + Business Media 2017 Journal of materials science Materials in electron Vol.28 No.22