Experimental Investigation of Adiabatic Film Cooling Effectiveness and Heat Transfer Coefficients over a Gas Turbine Blade Leading Edge Configuration

Increasing the rotor inlet temperature is one of the key technologies in raising gas turbine engine performance, for which the turbine blades need to be cooled. Film cooling is one of the efficient cooling techniques to cool the hot section components of a gas turbine engines. In film cooling, a gas which is cooler than the main stream is passed onto the external surface via small slots or rows of holes within the surface. In the present study, the experimental investigation was conducted for an adiabatic film effectiveness and heat transfer coefficients over a gas turbine blade leading edge model at a subsonic cascade tunnel facility of CSIR-National Aerospace Laboratories, Bangalore. This study aims at investigating the effect of blowing ratio on the adiabatic film cooling effectiveness and heat transfer coefficients experimentally for the 20 Degree hole inclination angles gas turbine blade leading edge model. The blade leading edge model was fabricated using the Rapid Proto Typing method using a very low thermal conductivity nylon based alloy material. This study aims at bringing the optimized blowing ratio values for the considered hole diameter of leading edge configuration. The comparative results showed that the blowing ratio beyond 2.0 does not have any improvement in the adiabatic film cooling effectiveness

Educational films for improving screening and self-management of gestational diabetes in India and Uganda (GUIDES): study protocol for a cluster-randomised controlled trial.

BACKGROUND: The prevalence of gestational diabetes mellitus (GDM) is rising rapidly in many low- and middle-income countries (LMICs). Most women with GDM in LMICs are undiagnosed and/or inadequately managed due to a lack of knowledge and skills about GDM on the part of both providers and patients. Following contextual analysis, we developed an educational/behavioural intervention for GDM delivered through a package of culturally tailored films. This trial aims to evaluate whether the intervention can improve the timely detection and management of GDM in two LMIC settings. METHODS: Two independent cluster randomised controlled trials, one each to be conducted in Uganda and India. Thirty maternity facilities in each country have been recruited to the study and randomised in a 1:1 ratio to the intervention and control arms. The intervention comprises of three interconnected sets of films with the following aims: to improve knowledge of GDM guidelines and skills of health providers, to raise awareness of GDM screening among pregnant women and their families, and to improve confidence and skills in self-management among those diagnosed with GDM. In facilities randomised to the intervention arm, a GDM awareness-raising film will be shown in antenatal care waiting rooms, and four films for pregnant women with GDM will be shown in group settings and made available for viewing on mobile devices. Short films for doctors and nurses will be presented at professional development meetings. Data will be collected on approximately 10,000 pregnant women receiving care at participating facilities, with follow-up at 32 weeks gestational age and 6 weeks postnatally. Women who self-report a GDM diagnosis will be invited for a clinic visit at 34 weeks. Primary outcomes are (a) the proportion of women who report a GDM diagnosis by 32 weeks of pregnancy and (b) glycaemic control (fasting glucose and HbA1C) in women with GDM at ~34 weeks of pregnancy. The secondary outcome is a composite measure of GDM-related adverse perinatal-neonatal outcome. DISCUSSION: Screening and management of GDM are suboptimal in most LMICs. We hypothesise that a scalable film-based intervention has the potential to improve the timely detection and management of GDM in varied LMIC settings. TRIAL REGISTRATION: ClinicalTrials.gov NCT03937050 , registered on 3 May 2019. Clinical Trials Registry India CTRI/2020/02/023605 , registered on 26 February 2020

Alkaline residues and the environment: A review of impacts, management practices and opportunities

Around two billion tonnes of alkaline residues are produced globally each year by industries such as steel production, alumina refining and coal-fired power generation, with a total production estimate of 90 billion tonnes since industrialization. These wastes are frequently stored in waste piles or landfills, and can be an environmental hazard if allowed to generate dust, or if rainwater infiltrates the waste. This review will focus on the environmental impacts associated with alkaline residues, with emphasis on the leachates produced by rainwater ingress. Many alkaline industrial wastes can produce leachates that are enriched with trace metals that form oxyanions (e.g. As, Cr, Mo, Se, V), which can be very mobile in alkaline water. The management options for the residues and their leachates are also discussed, distinguishing active and passive treatment options. Potential reuses of these materials, in construction materials, as agricultural amendments, and in environmental applications are identified. The mechanisms of carbon sequestration by alkaline residues are assessed, and the potential for enhancing its rate as a climate change off-setting measure for the industry is evaluated. The potential for recovery of metals critical to e-technologies, such as vanadium, cobalt, lithium and rare earths, from alkaline residues is considered. Finally research needs are identified, including the need to better understand the biogeochemistry of highly alkaline systems in order to develop predictable passive remediation and metal recovery technologies

CFD Simulation of Open-cell Aluminum Metal Foams for Pressure Drop Characterization

Many researchers have done the CFD simulation of open-cell aluminum metal foams with a unit cell with periodic boundary conditions. However, this does not represent a real life situation, as the foam-fluid interactions cannot be properly modeled. In the present study the simulation is done for metal foam with the more number of foam cells to proximate the conditions close to the actual situations. The CFD simulation of open-cell aluminum metal foams was done using ANSYS FLUENT. The results are obtained by solving the Continuity, Momentum and Energy equations and standard k- ε turbulence model is used for simulation. The boundary conditions applied are same as those applied during the experiments conducted at Heat Transfer Lab, National Aerospace Laboratories, Bangalore. In this study the Aluminum Alloy (Al 6101-T6) metal foam of pore density 10 ppi is used for CFD analysis

Experimental and Numerical Investigation of Effect of Blowing Ratio on Film Cooling Effectiveness and Heat Transfer Coefficient over a Gas Turbine Blade Leading Edge Film Cooling Configurations

Film cooling is one of the cooling techniques to cool the hot section components of a gas turbine engines. The gas turbine blade leading edges are the vital parts in the turbines as they are directly hit by the hot gases, hence the optimized cooling of gas turbine blade surfaces is essential. This study aims at investigating the film cooling effectiveness and heat transfer coefficient experimentally and numerically for the three different gas turbine blade leading edge models each having the one row of film cooling holes at 15, 30 and 45 degrees hole orientation angle respectively from stagnation line. Each row has the five holes with the hole diameter of 3mm, pitch of 20mm and has the hole inclination angle of 20deg. in spanwise direction. Experiments are carried out using the subsonic cascade tunnel facility of National Aerospace Laboratories, Bangalore at a nominal flow Reynolds number of 1,00,000 based on the leading edge diameter, varying the blowing ratios of 1.2, 1.50, 1.75 and 2.0. In addition, an attempt has been made for the film cooling effectiveness using CFD simulation, using k-€ realizable turbulence model to solve the flow field. Among the considered 15, 30 and 45 deg. models, both the cooling effectiveness and heat transfer coefficient shown the increase with the increase in hole orientation angle from stagnation line. The film cooling effectiveness increases with the increase in blowing ratio upto 1.5 for the 15 and 30 deg. models, whereas on the 45 deg. model the increase in effectiveness shown upto the blowing ratio of 1.75. The heat transfer coefficient values showed the increase with the increase in blowing ratio for all the considered three models. The CFD results in the form of temperature, velocity contours and film cooling effectiveness values have shown the meaningful results with the experimental values

Cultivation of an indigenous Chlorella sorokiniana with phytohormones for biomass and lipid production under N-limitation

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Zoster and its lurking shadow

A large number of oral mucosal lesions result in severe post-affliction deficits. One such defect is neurological fall out. Herpes zoster is a condition that occasionally results in a dreadful post-infection neuralgic pain. Although shingles is generally regarded as a self-limited condition, it can take several weeks to resolve and has the potential for development of complications. To identify this as well as appropriate management is required. Patients affected are in such severe distress that alleviation of pain and successful treatment protocol should be the primary consideration. We report one such case, which was successfully treated, and also intend to highlight the current concepts in the management of such cases