Arvind Gangoli Rao

Delft University of Technology | TU · Department of Aerodynamics, Wind Energy, Flight Performance and Propulsion (AWEP)

Aviation is forecasted to grow at around 5% every year for next few decades. The internal air traffic within Asia has increased substantially and is driving the growth in aviation. With the increasing urbanization, a substantial part of the air traffic within Asia and around the world is marked by travel between mega cities (with population of arou...

Reduction of CO 2 and NOx emission is one of the main challenges in civil aviation. Even though there has been substantially reduction in CO2 and NOx emission over the years, the increase air-traffic outpaced the decrease in emissions. With global warming being one of the main problems being faced by humanity, the emissions from aviation cannot be...

Future demands for sustainability indicate that aircraft should be fuel efficient, less noisy and less polluting. However, with the conventional incremental aviation technologies, it seems there is very little chance to meet these requirements. This paper demonstrates a novel hybrid engine concept for future Blended Wing Body (BWB) aircraft. The pr...

The Advisory Council for Aeronautics Research in Europe (ACARE) has set ambitious objectives for civil aviation for 2020 and beyond; the major being reduction of CO 2 emission by more than 50%, for which significant improvements in the aircraft, propulsion and operational systems are required. However, at this moment it appears that this goal can n...

Jet impingement is one of the best methods for achieving high heat transfer coefficient in single phase and has been a topic of active research for several decades, involving both experiments and computations. Most of the research on multiple jets have been carried out for an array of jets in the high Reynolds number regime. To increase the applica...

A CFD-based design study for ducted Boundary-Layer Ingesting (BLI) propulsion is presented , which focusses on BLI engines which are small enough to operate well within the boundary and thus do not ingest air at free-stream Mach number at their design condition. Such designs are expected to require different design rules than either conventional un...

HYLENA will demonstrate the feasibility and high level performance of a contoured SOFC-GT Engine fueled with LH2. The SOFC-GT concept is an engine that integrates a Solid Oxide Fuel Cell into a turbomachine, in order to make use of the Brayton cycle to valorize the heat generated by the fuel cell, in addition to electrical power supplied eMotors. I...

Civil aviation has been going through continuous development since the invention of jet engines. With the continuously increasing demands, there are still challenges to be faced in order to meet the emission goals. Even with operational improvements, novel combustion technologies with hydrogen and drop-in fuels and increased component efficiencies,...

HYLENA will investigate, develop and optimize an innovative, highly efficient integrated hydrogen powered, electrical aircraft propulsion concept for short and medium range. It will achieve significant climate impact reduction by being completely carbon neutral with radical increase of overall efficiency. The full synergistic use of a) an electr...

The climate impact of aviation is considerably different from that of other transport modes. The turbofan engine’s efficiency can be increased by increasing the Operating Pressure Ratio (OPR), bypass ratio (BPR) and Turbine Inlet Temperature (TIT), thereby reducing CO2 and H2O emissions. However, this may have an adverse effect on the secondary emi...

Large eddy simulation (LES) paradigms are employed to analyse the internal flow field of a lean premixed swirl-stabilized combustor with axial air injection at both non-reacting and reacting conditions, for a methane and a methane-hydrogen fuel mixture. The thickened flame combustion model (TFM) with detailed chemical kinetic mechanism is employed...

Lean-premixed swirl-stabilized combustion is a successful strategy to reduce pollutant emissions. However, these combustion systems are especially prone to thermoacoustic instabilities. The precessing vortex core (PVC) plays a significant role in suppressing or exciting those instabilities. Therefore, it is necessary to predict the PVC dynamics in...

The power sector accounts for around 40% of global energy-related CO2 emissions. Its decarbonization by switching to low-carbon renewables is essential for a sustainable future. Existing electrical grids, however, have limited capacity to absorb the variability introduced by these new energy sources and rely largely on natural-gas-based power gener...

Boundary-layer instability on a rotating cone induces coherent spiral vortices that are linked to the onset of laminar–turbulent transition. This type of transition is relevant to several aerospace systems with rotating components, e.g., aeroengine nose cones. Because a variety of options exist for the nose-cone shapes, it is important to know how...

The fuel efficiency of turbofan engines has improved significantly, hence reducing aviation’s CO2 emissions. However, the increased operating pressure and temperature for fuel efficiency cause adverse effects on NOx emissions. Therefore, a novel engine concept, which can reduce NOx emissions without affecting the cycle efficiency, is of high intere...

Flameless Combustion is an interesting low NOx combustion technology for gas turbine engines. In order to design systems for stringent performance standards, it is important to understand emission formation in this regime. To this end, the characteristics of a combustor capable of operating in the Flameless regime are studied. Particle Image Veloci...

The concept of an "Auxiliary Power and Propulsion Unit" (APPU) is introduced, which consists of a Boundary-layer-ingesting (BLI) propulsor with an engine mounted at the rear of an passenger aircraft fuselage, replacing the Auxiliary Power Unit (APU) and contributing around 10% of total cruise thrust, as well as auxiliary power. This APPU unit is us...

This is a design synthesis exercise in which an A320 was modified to use Ammonia as a fuel

Boundary-layer ingestion (BLI) is a propulsor–airframe integration technology that promises substantial fuel consumption benefits for future civil aircraft. This paper discusses an experimental study, conducted within the European Union–funded Horizon 2020 CENTRELINE project, on the aerodynamic performance of an aircraft with a BLI propulsor integr...

This work shows the behavior of an unstable boundary-layer on rotating cones in high-speed flow conditions: high Reynolds number [Formula: see text], low rotational speed ratio [Formula: see text], and inflow Mach number M = 0.5. These conditions are most-commonly encountered on rotating aeroengine nose cones of transonic cruise aircraft. Although...

The AeroCity is a new form of transportation concept that has been developed to provide high-speed ground transportation at a much lower cost than the existing high-speed railway. Utilizing the Wing-in-Ground (WIG) effect, the AeroCity vehicle does not require complex infrastructures like other contemporary concepts, such as the Hyperloop or Maglev...

Boundary-layer ingestion (BLI) has been proposed as one of the novel airframe–engine integration technologies to reduce aircraft fuel consumption. The current numerical analysis involves the evaluation of the effect of fuselage design on the power consumption of a boundary-layer ingesting propulsor modeled as an actuator volume without nacelle. An...

Boundary Layer Ingestion (BLI) is a promising propulsion integration technology capable of enhancing aircraft propulsive efficiency. The Propulsive Fuselage Concept (PFC), a tube-and-wing configuration with an aft-fuselage-mounted BLI propulsor, is particularly suited for BLI. Although extensively studied on a system level, the aerodynamic performa...

View Video Presentation: https://doi.org/10.2514/6.2021-2467.vid Boundary Layer Ingestion (BLI) is a technology that promises fuel consumption benefits for future civil aircraft. However, it introduces detrimental aerodynamic interactions between the propulsor and the airframe. In particular, the inflow to the BLI propulsor is affected by the flow...

Aviation is an important contributor to the global economy, satisfying society’s mobility needs. It contributes to climate change through CO 2 and non-CO 2 effects, including contrail-cirrus and ozone formation. There is currently significant interest in policies, regulations and research aiming to reduce aviation’s climate impact. Here we model th...

Centrifugal instability of the boundary layer is known to induce spiral vortices over a rotating slender cone that is facing an axial inflow. This paper shows how a deviation from the symmetry of such axial inflow affects the boundary layer instability over a rotating slender cone with half-angle ψ = 15◦. The spiral vortices are experimentally dete...

Future energy and transport scenarios will still rely on gas turbines for energy conversion and propulsion. Gas turbines will play a major role in energy transition and therefore gas turbine performance should be improved, and their pollutant emissions decreased. Consequently, designers must have accurate performance and emission prediction tools....

The society is going through transformations at a rate that is unprecedented in human history. One such transformation is the energy transition, which will affect almost every facet of our society. Gas turbine engines are state of the art machines, a backbone of modern society, and used in various applications, right from power generation to propel...

Aviation is the backbone of our modern society. In 2019, around 4.5 billion passengers travelled through the air. However, at the same time, aviation was also responsible for around 5% of anthropogenic causes of global warming. The impact of the COVID-19 pandemic on the aviation sector in the short term is clearly very high, but the long-term effec...

In the pursuit of reducing the fuel burn, future aircraft configurations will feature several types of improved propulsion systems, e.g. embedded engines with boundary layer ingestion, high-bypass ratio engines with short intakes, etc. Depending on the design and phase of flight, the engine fan will encounter inflow distortion of varying strength,...

The combustion properties of hydrogen make premixed hydrogen-air flames prone to flashback. Several combustor concepts have been proposed and studied in the past few years to tackle the problem of flame flashback in premixed high hydrogen fuel combustors. This study looks at one of the concepts which uses the Aerodynamically Trapped Vortex to stabi...

With the growing pressure to reduce the environmental footprint of aviation, new and efficient propulsion systems must be investigated. The current research looks at the operating characteristics of a turbofan engine in a parallel hybrid-electric propulsion system. Electric motors are used to supply power in the most demanding take-off and climb ph...

This report is the final report of the design synthesis exercise. The challenge of this exercise was to design a high capacity aircraft optimised for short range missions. This report was written by a group of 10 students working on the project along with the guidance of faculty members. It intends to give a complete overview of the preliminary des...

The Flameless Combustion (FC) regime has been pointed out as a promising combustion technique to lower the emissions of nitrogen oxides (NOx) while maintaining low CO and soot emissions, as well as high efficiencies. However, its accurate modeling remains a challenge. The prediction of pollutant species, especially NOx, is affected by the usually l...

There is an error in Equation 21 of the original article. The weight of the battery is a function of the energy stored at the start and will not vary during flight whereas the fuel weight will vary as a function of the energy level. Hence, the correct equation is.

Wake-filing propulsion by means of Boundary Layer Ingestion has the potential to increase the aero-propulsive efficiency of next-generation aircraft.For the Propulsive Fuselage Concept in particular, the integrated aft-mounted fan operates directly in the boundary-layer flow of the fuselage. Therefore, the flow around the fuselage represents the in...

Infrared thermography is applied to measure the spiral vortices in the boundary layer over a rotating cone under axial inflow. The data sets are analysed using proper orthogonal decomposition (POD). A criterion based on the signal-to-noise ratio is defined for the selection of relevant POD modes, such that a low-order reconstruction with reduced me...

The flameless combustion (FC) regime is a promising technology for gas turbines, as it potentially yields lower NOx emissions while maintaining high combustion efficiencies. However, the application of FC to gas turbines is still challenging as required conditions for its occurrence depend on several factors such as reactants mixing, residence time...

One of the main challenges of future aircraft engines is to achieve low pollutant emissions while maintaining high combustion efficiencies and operability. The Flameless Combustion (FC) regime is pointed as one of the promising solutions due to its well-distributed reaction zones that yield low NO x emissions and oscillations. A dual-combustor conf...

Boundary layer instabilities and the formation of coherent spiral vortices over a rotating cone and ellipsoid are studied experimentally. It is found that under a non-axial inflow, the breaking of symmetry in the flow field significantly disturbs the coherence and delays the formation of spiral vortices to higher local Reynolds numbers (Re_l) and h...

Junction flow caused by the aerodynamic interaction between a wind-tunnel model and the support structure can largely influence the flowfield and hence the experimental results. This paper discusses a combined numerical and experimental study which was carried out to mitigate the model–support interference in a wind-tunnel test setup for the study...

The energy scenario is currently undergoing a rapid transition in the pursuit of increasing the share of renewable energy sources in order to reduce the global anthropogenic CO2 emission. However, since several of the renewable energy sources are intermittent in nature, like wind and solar, this intermittency gives rise to several problems in energ...

Since its discovery, the Flameless Combustion (FC) regime has been seen as a promising alternative combustion technique to reduce pollutant emissions of gas turbine engines. This combustion mode is often characterized by well-distributed reaction zones, which can potentially decrease temperature gradients, acoustic oscillations and, consequently NO...

Low flight altitude missions are a threat due to the combat aircraft's Infrared (IR) Signature Level (IRSL) as seen by ground-based IR-seeker. The bands in which, the aircraft is susceptible to a typical IR-guided Surface-to-Air Missile are 3-5 microns and 8-12 microns. The rear fuselage skin contributes substantially to the overall aircraft IRSL e...

This paper presents the performance assessment of a novel turbofan engine using two energy sources: Liquid Natural Gas (LNG) and kerosene, called Multi-Fuel Hybrid Engine (MFHE). The MFHE is a new engine concept consisting of several novel features, such as a contra-rotating fan to sustain distortion caused by boundary layer ingestion, a sequential...

As the overall pressure ratio (OPR) and turbine inlet temperature (TIT) of modern gas turbines are constantly being increased in the pursuit of increasing efficiency and specific power, the effect of bleed cooling air on the engine performance is increasingly becoming important. During the thermodynamic cycle analysis and optimization phase, the co...

With civil aviation growing at around 4.7% per annum, the environmental footprint of aviation is increasing. Moreover, the use of kerosene as a fuel accelerates the depletion of non-renewable fossil fuels and increases global warming. Hence, the aviation industry has to come up with new technologies to reduce its environmental impact and make aviat...

The Advisory Council for Aeronautics Research in Europe (ACARE) has set an ambitious array of objectives to be accomplished by 2050 for civil aviation. It is often claimed that complying with those targets will not require evolution but, rather, revolution. If the growth in aviation has to be sustained in the future, then we must come up with radic...

Air traffic is important to our society and guarantees mobility especially for long distances. Air traffic is also contributing to climate warming via emissions of CO2 and various non-CO2 effects, such as contrail-cirrus or increase in ozone concentrations. Here we investigate the climate impact of a future aircraft design, a multi fuel blended win...

Since its discovery, the flameless combustion (FC) regime has been a promising alternative to reduce pollutant emissions of gas turbine engines. This combustion mode is characterized by well-distributed reaction zones, which potentially decreases temperature gradients, acoustic oscillations, and NO x emissions. Its attainment within gas turbine en...

The potential environmental benefits of hybrid electric regional turboprop aircraft in terms of fuel consumption are investigated. Lithium–air batteries are used as energy source in combination with conventional fuel. A validated design and analysis framework is extended with sizing and analysis modules for hybrid electric propulsion system compone...

The historical trends of reduction in fuel consumption and emissions from aero engines have been mainly due to the improvement in the thermal efficiency, propulsive efficiency and combustion technology. The engine Overall Pressure Ratio (OPR) and Turbine Inlet Temperature (TIT) are being increased in the pursuit of increasing the engine thermal eff...

The effect of film cooling on the aerodynamic performance of turbine blades is becoming increasingly important as the gas turbine operating temperature is being increased in order to increase the performance. The current paper investigates the effect of blowing ratio on the aerodynamic losses of a symmetric airfoil by pressure measurements and Part...

Aerocity is a new type of high-speed transportation system which exploits aerodynamic shaping of the vehicle and wing-in-ground effect to create lift efficiently. The main advantage of this concept as compared to existing and contemporary high-speed transportation systems is its ability to use cheap infrastructure. Since the high infrastructure and...

This paper focuses on the off-design performance of a turbofan engine with an interstage turbine burner (ITB). The ITB is an additional combustion chamber located between the high-pressure turbine (HPT) and the low-pressure turbine (LPT). The incorporation of ITB in an engine can provide several advantages, especially due to the reduction in the HP...

Substantial research is being devoted to technologies which have the potential of increasing aircraft propulsion efficiency. Evolutionary gains can be obtained by improving on traditional aspects like blade cooling, high-temperature materials, turbomachinery aerodynamics, etc. On the contrary, the adoption of a different thermodynamic cycle configu...

The article presents a new procedure to calculate the wall temperature of film-cooled turbine blades. The methodology utilises semi-empirical relations for film cooling effectiveness developed for a flat plate. The correlations are corrected a-posteriori with parameters (Mach number, pressure, etc) resulting from aerodynamic analysis, performed by...

The Advisory Council for Aeronautics Research in Europe (ACARE) has set an ambitious array of objectives to be accomplished by 2050 for civil aviation. It is often claimed that complying with those targets will not require evolution but, rather, revolution. If the growth in aviation has to be sustained in the future, then we must come up with radic...