Performance Evaluation of Vortex Generator of Finite Thickness to Augment Heat Transfer in a Compact Heat Exchanger

The effect of non dimensional thickness of a winglet type vortex generator is investigated in terms of heat transfer rate, stream-wise vortices and flow losses in a plate fin heat exchanger with triangular inserts as secondary fins. The winglet type vortex generators are mounted alternatively on the upper and lower plates of the heat exchanger to disrupt the flow in the triangular domain formed by the inserts. The fluid flow within the duct is considered to be confined and laminar. While the hydrodynamic flow is fully developed, the thermal characteristics are assumed to be in developing stage under isothermal boundary conditions. The winglet is located in the duct where the flow is fully developed (Xi = 2.765 w.r.t. leading edge) at an angle of 27o with respect to the bulk flow direction. The aforesaid performance characteristics are computed numerically by solving the mass continuity, momentum and energy equations. Computational results clearly show an enhancement of 12.91% in the heat transfer rate (quantified as Num/ Nuo) for an increase in non dimensional thickness c/2H from 0.00 to 0.05. Besides, the pressure drop penalty is found to be only 3.8% at Re = 150. The results have also been substantiated by carrying out experiments on a scaled model configuration. Three dimensional velocity components are verified behind the winglet to ensure the stable flow field for non dimensional thickness of winglet c/2H=0.05 and Reynolds number of 350

Advances in modelling of biomimetic fluid flow at different scales

The biomimetic flow at different scales has been discussed at length. The need of looking into the biological surfaces and morphologies and both geometrical and physical similarities to imitate the technological products and processes has been emphasized. The complex fluid flow and heat transfer problems, the fluid-interface and the physics involved at multiscale and macro-, meso-, micro- and nano-scales have been discussed. The flow and heat transfer simulation is done by various CFD solvers including Navier-Stokes and energy equations, lattice Boltzmann method and molecular dynamics method. Combined continuum-molecular dynamics method is also reviewed

Prediction and optimization of work-piece temperature during 2.5-D milling of Inconel 625 using regression and Genetic Algorithm

The estimation of heat distribution during metal cutting is essential, as it contributes in workpiece deflection and quality of the machining. Inconel 625 is a high strength nickel-based superalloy that is broadly used in aerospace, automobile and nuclear applications. It is machining is very difficult due to their low thermal conductivity, high hardness even at high temperature. Therefore, a challenge in front of industries arises due to the properties of the material, high temperature of work-piece during cutting and hence might the cause of work-piece deformation & thermal stresses. However, by proper selection of cutting parameters and tool geometry, the work-piece temperature could be minimized. The present work emphasizes on the impact of machining parameters such as cutting speed, feed, depth of cut and step-over on the work-piece temperature during 2.5-D milling under dry condition. Box–Behnken design (BBD) model has been considered for three levels of input process parameters. The temperature of the work-piece has been estimated with the help of pyrometer type thermometer. The significance and adequacy of the proposed model and effects of process parameter on the temperature of work-piece has been carried out through ANOVA & regression methodology. The prognostic model in this study is generating values of the work-piece temperature which is close to those readings recorded experimentally. To optimize the machining parameters for minimization of work-piece temperature Genetic Algorithm has been applied on the prognostic model. Conformational experiments with a 5% error have also been performed to validate the results

Fatigue Life Assessment of 65Si7 Leaf Springs: A Comparative Study

x + 130 hlm.; 14,5 x 21 c

Kidney and Cardiovascular Effects of Canagliflozin According to Age and Sex: A Post Hoc Analysis of the CREDENCE Randomized Clinical Trial

Rationale & Objective: It is unclear whether the effect of canagliflozin on adverse kidney and cardiovascular events in those with diabetic kid-ney disease varies by age and sex. We assessed the effects of canagliflozin among age group categories and between sexes in the Canagli-flozin and Renal Endpoints in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) study.Study Design: Secondary analysis of a random-ized controlled trial. Setting & Participants: Participants in the CREDENCE trial. Intervention: Participants were randomly assigned to receive canagliflozin 100 mg/d or placebo.Outcomes: Primary composite outcome of kid-ney failure, doubling of serum creatinine con-centration, or death due to kidney or cardiovascular disease. Prespecified secondary and safety outcomes were also analyzed. Out-comes were evaluated by age at baseline (<60, 60-69, and >_70 years) and sex in the intention-to-treat population using Cox regression models.Results: The mean age of the cohort was 63.0 & PLUSMN; 9.2 years, and 34% were female. Older age and female sex were independently associ-ated with a lower risk of the composite of adverse kidney outcomes. There was no evidence that the effect of canagliflozin on the primary outcome (acomposite of kidney failure, a doubling of serum creatinine concentration, or death from kidney or cardiovascular causes) differed between age groups (HRs, 0.67 [95% CI, 0.52-0.87], 0.63 [0.4 8-0.82], and 0.89 [0.61-1.29] for ages <60, 60-69, and >_70 years, respectively; P = 0.3 for interaction) or sexes (HRs, 0.71 [95% CI, 0.5 4-0.95] and 0.69 [0.56-0.8 4] in women and men, respectively; P = 0.8 for interaction). No differences in safety outcomes by age group or sex were observed.Limitations: This was a post hoc analysis with multiple comparisons.Conclusions: Canagliflozin consistently reduced the relative risk of kidney events in people with diabetic kidney disease in both sexes and across age subgroups. As a result of greater background risk, the absolute reduction in adverse kidney outcomes was greater in younger participants.Funding: This post hoc analysis of the CREDENCE trial was not funded. The CREDENCE study was sponsored by Janssen Research and Development and was conducted collaboratively by the sponsor, an academic-led steering committee, and an academic research organization, George Clinical.Trial Registration: The original CREDENCE trial was registered at ClinicalTrials.gov with study number NCT02065791