Aditya Kolakoti

Para avan ar, um navio precisa de impulso, que gerado pela rota o da h lice atr s do casco. As h lices s o usadas para gerar impulso para propulsionar ve culos mar timos. A h lice gera impulso em virtude da diferen a de press o entre duas superf cies da p da h lice, chamadas de face e verso. O ngulo de incid ncia do fluxo desempenha um papel importante na gera o dessa diferen a de press o em cada se o da p (que uma se o aerodin mica em geral). Uma h lice de passo control vel pode ajustar a incid ncia do fluxo de entrada e oferecer um melhor controlo sobre o impulso gerado por ela. Tradicionalmente, o impulso e o bin rio de uma h lice s o previstos por testes em modelo. Isso requer mais tempo, m o de obra, espa o e custos. Atualmente, a CFD est a tornar-se popular para projetos hidrodin micos, pois proporciona uma economia relativa em tempo, m o de obra, espa o e custos.

Per avanzare, una nave ha bisogno di spinta, che viene generata dalla rotazione dell'elica dietro lo scafo. Le eliche vengono utilizzate per generare la spinta necessaria a propellere i veicoli marini. L'elica genera spinta grazie alla differenza di pressione tra le due superfici della pala dell'elica, chiamate faccia e dorso. L'angolo di incidenza del flusso gioca un ruolo fondamentale nella generazione di questa differenza di pressione su ogni sezione della pala (che in genere una sezione aerodinamica). Un'elica a passo variabile pu regolare l'incidenza del flusso in entrata e offrire un migliore controllo sulla spinta da essa generata. Tradizionalmente, la spinta e la coppia di un'elica vengono previste mediante prove su modello. Ci richiede pi tempo, manodopera, spazio e costi. Attualmente, la CFD sta diventando popolare per i progetti idrodinamici in quanto consente un risparmio relativo in termini di tempo, manodopera, spazio e costi.

Aby poruszac się do przodu, statek potrzebuje ciągu, kt ry jest generowany przez obracające się śruby napędowe umieszczone za kadlubem. Śruby napędowe slużą do generowania ciągu napędzającego pojazdy morskie. Śruba napędowa generuje ciąg dzięki r żnicy ciśnień między dwiema powierzchniami lopaty śruby napędowej, zwanymi powierzchnią czolową i tylną. Kąt natarcia przeplywu odgrywa istotną rolę w generowaniu tej r żnicy ciśnień na każdej sekcji lopaty (kt ra jest og lnie sekcją aerodynamiczną). Śruba napędowa o regulowanym skoku może dostosowac kąt natarcia naplywającego strumienia i zapewnic lepszą kontrolę nad generowanym przez nią ciągiem. Tradycyjnie ciąg i moment obrotowy śruby napędowej są przewidywane na podstawie test w modelowych. Wymaga to więcej czasu, sily roboczej, przestrzeni i koszt w. Obecnie CFD zyskuje popularnośc w projektowaniu hydrodynamicznym, ponieważ zapewnia względną oszczędnośc czasu, sily roboczej, przestrzeni i koszt w.

Pour avancer, un navire a besoin d'une pouss e, qui est g n r e par la rotation de l'h lice situ e derri re sa coque. Les h lices sont utilis es pour g n rer la pouss e n cessaire la propulsion des v hicules marins. L'h lice g n re une pouss e gr ce la diff rence de pression entre les deux surfaces de la pale, appel es face et dos. L'angle d'incidence du flux joue un r le majeur dans la g n ration de cette diff rence de pression sur chaque section de la pale (qui est g n ralement une section a rodynamique). Une h lice pas variable peut ajuster l'incidence du flux entrant et offrir un meilleur contr le de la pouss e g n r e par celui-ci. Traditionnellement, la pouss e et le couple d'une h lice sont pr dits par des essais sur mod le. Cela demande plus de temps, de main-d'oeuvre, d'espace et d'argent. l'heure actuelle, la CFD est de plus en plus utilis e pour les conceptions hydrodynamiques, car elle permet de gagner du temps, de la main-d'oeuvre, de l'espace et de l'argent.

Um sich fortzubewegen, ben tigt ein Schiff Schubkraft, die durch die Drehung des Propellers hinter dem Rumpf erzeugt wird. Propeller werden verwendet, um Schubkraft zu erzeugen und Wasserfahrzeuge anzutreiben. Der Propeller erzeugt Schubkraft aufgrund des Druckunterschieds zwischen zwei Oberfl chen des Propellerblatts, die als Vorderseite und R ckseite bezeichnet werden. Der Anstellwinkel der Str mung spielt eine wichtige Rolle bei der Erzeugung dieses Druckunterschieds ber jeden Blattabschnitt (der im Allgemeinen ein Tragfl chenabschnitt ist). Ein Propeller mit verstellbarer Steigung kann den Anstellwinkel der einstr menden Str mung anpassen und erm glicht eine bessere Kontrolle ber den dadurch erzeugten Schub. Traditionell werden Schub und Drehmoment eines Propellers durch Modellversuche vorhergesagt. Dies erfordert mehr Zeit, Personal, Platz und Kosten. Gegenw rtig wird CFD f r hydrodynamische Konstruktionen immer beliebter, da es relative Einsparungen an Zeit, Personal, Platz und Kosten erm glicht.

Les conomies d' nergie et l'am lioration de l'efficacit des syst mes nerg tiques constituent une t che importante sur la voie d'un avenir plus durable. L'int r t r cent pour les syst mes de production combin e de chaleur et d' lectricit (PCCE) solaires thermiques petite chelle a co ncid avec la croissance de la demande d'approvisionnement en lectricit distribu e dans les zones mal desservies par les centrales lectriques centralis es. Une approche technique potentielle pour r pondre cette demande est le capteur solaire thermique plat coupl un moteur thermique cycle organique de Rankine (ORC).

Il risparmio energetico e il miglioramento dell'efficienza dei sistemi energetici sono un compito importante nel percorso verso un futuro pi sostenibile. Il recente interesse per i sistemi di cogenerazione solare termica su piccola scala ha coinciso con la crescita della domanda di forniture elettriche distribuite in aree scarsamente servite da centrali elettriche centralizzate. Un potenziale approccio tecnico per soddisfare questa domanda il collettore solare termico piatto accoppiato a un motore termico a ciclo Rankine organico (ORC).

Energieeinsparungen und Effizienzverbesserungen von Energiesystemen sind eine wichtige Aufgabe auf dem Weg zu einer nachhaltigeren Zukunft. Das j ngste Interesse an kleinen solarthermischen Kraft-W rme-Kopplungssystemen (KWK) f llt mit der wachsenden Nachfrage nach dezentraler Stromversorgung in Gebieten zusammen, die von zentralen Kraftwerken schlecht versorgt werden. Ein m glicher technischer Ansatz zur Deckung dieser Nachfrage ist der Flachkollektor in Verbindung mit einem ORC-W rmekraftwerk (Organic Rankine Cycle).

In this present investigation, four important process parameters of catalyst concentration, molar ratio, reaction time, and reaction temperature were studied and optimized using Box Behnken assisted response surface method (RSM) and Genetic Algorithm (GA) to achieve the maximum mahua oil biodiesel yield. For this purpose, 27 experiments were conducted randomly based on the design matrix using statistical software MiniTab(R)2019. A maximum yield of 91.32% is achieved in RSM, catalyst concentration and reaction time are identified as influence parameters in biodiesel yield. GA modelling show an improvement of 4.96% in biodiesel yield compared to RSM approach. Both techniques are successfully tested in prediction and modelling the biodiesel yield from mahua oil. The obtained biodiesel from the transesterification process is blended with standard diesel fuel at various proportions (B10 to B90) and tested for different fuel properties. All the biodiesel blends are observed within the limits of international standards of ASTMD-6751 and EN-14214. The results indicate that the chosen models are highly accurate in achieving maximum biodiesel yield.

The exhaust emissions from diesel engines are increasing at a faster rate. To mitigate the challenge alternative fuels especially biodiesel is gaining importance. In general edible or non-edible oils are used for production of biodiesels. In this endeavor the main objective is to produce biodiesel from waste cooking oil which is available abundantly for low or even free of cost. In order to improve the biodiesel yield Taguchi based optimization technique is used. Total of 9 experiments were conducted and 92.17% biodiesel yield is achieved. From analysis of variance (ANOVA) the influence factor is identified and coefficient of determination is 99.59% which shows that the chosen model is highly accurate. Artificial intelligent techniques are also used to revalidate the Taguchi results.

Energy savings and efficiency improvements of energy systems are an important task on the path towards a more sustainable future. Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the flat plate solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine.

Biodiesels are known as ecofriendly and biodegradable fuels. The unique properties in Biodiesel like high Cetane number and excess molecular oxygen helps the combustion complete with regulated emission. To mitigate the challenges of diesel engine exhaust emissions like NOx, HC, CO, CO2, PM and Smoke, biodiesel from different feed stocks of animal and plant oils are used. It has already proved experimentally that biodiesel can be used as an alternative fuel without changing the basic design of the existing engines. Despite of their advantages their practical application was limited to experimental stage this is due to the fact its high production cost. In this research an attempt was made to reduce the initial raw oil cost by utilizing the low cost feed stock of used cooking oil which was available at free of cost. In order to maximize the biodiesel yield advanced optimization techniques of Taguchi and Definitive screening design was adopted.