Ryoichi S. Amano

• Ph.D.
• Professor (Full) at University of Wisconsin–Milwaukee

In the dilution section of the gas turbine, the flow and thermal mixing between the cold radial jets and hot mainstream is always a matter of interest to generate a consistent thermal profile, extending the longevity of the turbine blades. Multiple researches explored the topic experimentally and numerically, and new designs have been evaluated, in...

Battery electric vehicles BEVs are suggested as a solution to reduce fossil fuel consumption. This study employs the Pareto chart and chi-square test to explore perceived barriers to the widespread adoption of BEVs in Jordan as a representative to MENA region countries. Based on a sample of 1481 respondents collected by an internet survey, it finds...

This paper explores imparting self-healing characteristics to metal matrices similar to what are observed in biological systems and are being developed for polymeric materials. To impart self-healing properties to metal matrices, a liquid healing method was investigated; the met hod consists of a container filled with low melting alloy acting as a...

In a solid rocket motor, when the aluminum based propellant combusts, the fuel is oxidized into alumina (Al2O3). It tends to agglomerate into molten droplets, impinge on the chamber walls, and then flow along the nozzle wall. Such agglomerates cause erosive damage. The focus of the current research is to characterize the agglomerate flow within the...

Prediction correlations of air bubble diameter and frequency in stagnant clean water were established. Eleven different orifice diameters were tested under flow rate of 0.05 – 0.15 SLPM. The resulted bubble size and frequency were traced using high-speed camera. It was found that the mean Sauter diameter and bubble frequency are in the range of 3.7...

Energy crises in the early 1970’s created awareness of the cost of wastewater treatment and the energy required for each stage. Aeration process was the focal point of energy saving research, due to its high power consumption, which led to change the use of coarse bubble aeration system to fine bubble aeration. Until now, all commercially existing...

Design and Optimization of 12-inch Kaplan Hydro-turbine working on 9 ft head

An experimental model of a combustor is used to create the hot and cold air streams, track the changes happened due to the mixing process and measured the effectiveness of the technique conducted. The mixing section was previously designed with staggered holes on the walls and later streamlined body was introduced. The comparative study emphasizes...

Investigation of liquid breakup mechanism is an important role to improve performance of solid rocket motor (SRM) to reduce the erosion damage near nozzle a throat section. Protection of the nozzle wall could be achieved by enhancing liquid breakup mechanism of the liquid alumina inside combustion chamber before bulk alumina slug erodes the nozzle...

Wind turbine blades undergo fatigue and their performance depletes as time progresses due to the formation of internal cracks. Self-healing in polymers is a unique characteristic used to heal the cracks inherently as they form. In this study, a new method is demonstrated for supplying the monomer (that is quintessential for the healing process) uni...

Despite being harvested thousands of years ago, wind energy was neglected during the industrial revolution because of the strong dependence on fossil fuels. However, after the alarming decrease in the fossil fuels reserves many have drawn their attentions back to a renewable energy technology, especially the wind energy. This paper presents some of...

Temperature uniformity after a mixing process plays a very important role in many applications. Non-uniform temperature at the entrance of the turbine in gas turbine systems has an adverse effect on the life of the blades. These temperature non-uniformities cause thermal stresses in the blades leading to higher maintenance costs. This paper present...

The effect of non-uniform temperature flow which comes in contact with the turbine blades is of paramount importance since the thermal damage that occur to the blade during its operation, is governed by the non-uniformities present in the oncoming flow. This thermal damage leads to increased maintenance cost and reduced life-span of the turbine bla...

A membrane for use in an air diffuser. The membrane includes a nub with a perforation. The nub and perforation and arranged and sized to create smaller bubbles of gas in a liquid column above the membrane.

This study presents a computational study of turbulent heat transfer through two-pass square-duct channel flows with several different turbulence models that were developed to improve near-wall predictions. To evaluate the performance of the advanced wall function (the analytical wall-function: AWF), the results were compared with experimental data...

The design and build of a Thermo-gravimetric analyzer (TGA) is discussed in this paper along with the preliminary data obtained. The TGA was designed for biomass pyrolysis and gasification. In the design it was taken in consideration decreasing the size as possible so as to decrease the area subject to heat losses as possible and to be capable of r...

The renewable energy is a promising field, which shows a lot of potential for future energy solutions. The design of the blade shows a lot effects on the efficiency of the wind turbine, and the design parameters governs the performance characteristics. This paper addresses a number of innovative blade designs that was developed by alterations made...

Aeration is the process at which air is added to water, an essential stage in wastewater treatment plants, since most of organic compounds are being treated through such an aeration process. This process also helps aerobic bacteria to survive from oxygenation to proliferate and digest organic materials. However, aeration consumes around 60% of the...

In order to invent a new near-wall treatment for turbulence in Computational Fluid Dynamics (CFD) simulation, an Analytical Wall Function (AWF) has been studied and shown that it is possible to work accurately with Reynolds Averaged Navier-Stokes (RANS) Simulation even for complicated geometry such as impinging jet flow or separation and reattachme...

Improvements in the thermal efficiency of a gas turbine can be obtained by operating it at high inlet temperatures. This high inlet temperature develops high thermal stresses on the turbine blades in addition to improving the performance. Cooling methodologies are implemented inside the blades to withstand those high temperatures. Four different co...

This paper presents the investigation of the macrostructure, microstructure, and solidification structure of an 316L/15% nickel coated TiC metal matrix composite produced by the LENS™ process. The focus of this work was to 1) identify the solidification structure and to estimate growth/cooling rates at the solid/liquid interface, 2) identify and qu...

Gas turbines are extensively used for aircraft propulsion, land-based power generation, and various industrial applications. With an increase in turbine rotor inlet temperatures, developments in innovative gas turbine cooling technology enhance the efficiency and power output; these advancements of turbine cooling have allowed engine designs to exc...

This paper addresses a study of air bubble creation in wastewater treatment system using both computational fluid dynamic (CFD) and experimental techniques. Based on the results found in this work, it was found that the bubble size depends on several factors such as flow rate, inlet pressure and contact angle for rubber membrane. Among these factor...

Aeration Is an essential stage In wastewater treatment plants. The main purpose of aeration Is to treat the organic contaminants in wastewater by activating aerobic: bacteria. Obviously, aerobic: bacteria need oxygen, which is provided by the aeration system, to proliferate and digest organic materiails. However, aeration is an energy demanding pro...

This study addresses the performance of wind turbine blade with different designs Both experimental and theoretical studies were conducted and analyzed the flow the power performance.

A basic understanding of flow characteristics over near wall region is essential to a complete study of Aerodynamics. In this study, a low turbulence, subsonic wind tunnel is used to perform the air flow velocity measurement, which are used to validate the Large-Eddy Simulation (LES) code for predictions of a wind turbine flow behavior. Hotwire pro...

Focusing on aerodynamics of wind turbines, this book presents advanced topics including: Basic Theory for Wind turbine Blade Aerodynamics; Dynamics-Based Health Monitoring and Control of Wind Turbine Rotors; Experimental Testing of Wind Turbines using Wind Tunnels with an Emphasis on Small-Scale Wind Turbines under Low-Reynolds Numbers; Computation...

Notice of withdrawal : The following article from Water and Environment Journal, ‘K La relation with bubble size, bubble release rate and number of bubbles’ by Ammar A T Alkhalidi and Ryo S. Amano, published online on 4 December 2013 in Wiley Online Library ( wileyonlinelibrary.com ), has been withdrawn by agreement between the journal Editor‐in‐Ch...

In this work a prediction was numerically modeled for a catalytically stabilized thermal combustion of a lean homogeneous mixture of air and hydrogen. The mixture flows in a narrow rectangular channel lined with a thin coating of platinum catalyst. The solution using an in-house code is based on the steady state partial differential continuity, mom...

The blade tip region in gas turbine encounters high thermal loads due to temperature difference and hence efforts for high durability and safe operations are essential. Improved and robust methods of cooling are required to downgrade heat transfer rate to turbine blades. The blade tip regions, which are exposed to high gas flow, suffers high local...

A number of studies have shown that the flow field exiting a combustor of a gas turbine cycle is highly non-uniform in pressure, velocity and, most importantly, temperature. Much research has been dedicated to the cooling of gas turbine blades using internal, film cooling, impingement jets, and pin/fin cooling technologies. Such designs allow for h...

This paper reports experimental and computational studies of flow and heat transfer through a square duct with a sharp 180 degree turn. The main purpose of this research is to study flow and heat transfer predictions of the Analytical Wall-Function (AWF). To compare the predicting performance of the AWF, the standard Log-Law Wall-Function (LWF) and...

Gas turbines are used in power production and aerojet propulsion, where the required form of energy is obtained by burning fuel, whether it is propulsion of an aircraft or simply electricity for our homes. Burning of fuels is accompanied by high temperature combustion products that must flow through a gas turbine to generate the power. These produc...

A study was conducted on convective heat transfer of a 55 impingement jet array (5×11) with a constant heat flux boundary condition. A spatial variation in a time-averaged Nusselt number, as well as a spanwise time-averaged Nusselt number, are presented for jet Reynolds numbers of 4,000, 8,000, 12,000, and 15,000 for jet to target standoff distance...

Optimization procedures are widely used in centrifugal compressor developments to enable high efficiency and wide operating ranges of compressors. It is very important to understand how to set the parameters and which parameter needs to be optimized. This paper demonstrates a case study on the importance of mechanical and structure combination opti...

Energy is the heart of today’s civilization and the demand seems to be increasing with our growing population. Alternative energy solutions are the future of energy, whereas the fossil-based fuels are finite and deemed to become extinct. The design of the wind turbine blade is the main governing factor that affects power generation from the wind tu...

Biomass is a renewable source of energy that was used for energy production since the discovery of fire. The production of power from biomass requires the use of gigantic masses of biomass. High rates of pollutants are produced from biomass combustion due to its natural composition. Biomass gasification can be used to decrease the harmful emissions...

High temperatures within the primary vane of a gas turbine system have been known to cause turbine blade failure due to high temperatures and stark, unexpected non-uniformities in the expelled gaseous product. Thus, to aid in the prevention of these costly and potentially dangerous failures, this study aimed to find ways to experimentally decrease...

The aeration phase within wastewater treatment is the most power consuming step required in the treatment of waste water. After the energy crisis in 1970s increasing attention has been paid for this step to reduce the energy cost [1]. Higher standard oxygen transfer efficiency (SOTE) reduces the amount of air required to aerate wastewater which red...

This paper presents the computational analysis of the dilution process involved in gas turbines order to cool the combustion gases to the desired temperature before it enters the turbine. Here, it should be noted that in order to focus only on the dilution process, non-reacting flow conditions were simulated and the complete system was reduced to m...

Improvement in thermal efficiency of gas turbine can be obtained by operating it at high inlet temperatures. In addition to improving the performance, the cons of high inlet temperature is high thermal stresses on the turbine blades. To improve life and performance of the blade, improved cooling technologies are desired. The main objective of this...

The objectives of this work are to study Laser Engineered Net Shaping (LENS TM ) produced materials and iden- tify the microstructures. Numerical method was used to examine the influence of materials' type and LENS TM process pa- rameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of...

This study is aimed at investigating the aerodynamic performance of the wind turbine blade with winglets and compares its performance in terms of the power generated with a regular straight blade without winglet. Adding a winglet to the wind turbine blade improves the power production without increasing the projected rotor area. A parameter study i...

This paper describes the experimental analysis of the heat transfer rate within an internal passage of a typical gas turbine blade using varied internal geometries. This method of alteration, using rib turbulator’s within the serpentine cooling passages of a hollow turbine blade, has proven to drastically cool turbine blades more significantly than...

The primary objective of this paper is to examine ways to increase the efficiency of water aeration process. This objective was completed through the use of a propeller and fan blade designs. Both Standard oxygen transfer efficiency (SOTE) and power reclamation were analyzed. Results of SOTE analysis indicated a decrease in efficiency, when compare...

This paper presents the comparison of the wake sizes and shapes between two different designs of a horizontal axis wind turbine (HAWT) rotor blades; one a straight edged and the other with a backward sweep. The straight edge blade was constructed so that it is optimal for on coming wind and rotation speeds with 7m/s and 23rpm. The blade has a lengt...

The objective of this project is to construct a CAD model for tubercle wind turbine. Once the model is developed a complete CFD analysis of the flow pattern around the wind turbine will be carried out. The main objective of the study is to analyze and compare the performance of the tubercle wind turbine with the usual wind turbine. The power develo...

A gas turbine combustor dilution process is modeled numerically using both 2-D and 3-D approaches, then an experimental set-up was designed and built for validation using standard air ducts. The combustor model is used to test various air cooling strategies with the goal of uniformly diluting combustion gas before it enters the turbine section. The...

The present paper is concerned with the numerical simulations of the turbulent flow and heat transfer in circular pipes using a low Reynolds number model for turbulence kinetic energy and its dissipation rate. Unlike the high Reynolds number turbulence models, the present solution procedure requires no special treatments near the pipe walls; i.e.,...

Optimization procedures are demanded by turbomachinery industries that enable to enhance compressor efficiency and wide operating ranges. Most of the design processes focuseither on aerodynamics or structure. However, the compressor design is an integration between aerodynamics and structure. This paper presents some recent developments of the aero...

Computational Fluid Dynamics (CFD) has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subje...

This study involves helping Manufacturing Company reduce overall production time, starting from concept through production, by finding and correlating the parameters of drag force, lift force, side force, pitching moment, yawing moment, and rolling moment of an Ahmed body, representative of a vehicle. The correlation parameters for the Ahmed body a...

Cooling channels are essential components of the modern gas turbine engines. Enhanced cooling techniques are allowing for increase in firing temperatures and thereby improving power and efficiency. Air bled from the compressor is passed through serpentine passages within the blade to take away the heat and keep the blade under operating temperature...

Aeration, a unit process in which air and water are brought into intimate contact, is an extremely important step in the process of wastewater treatment. It was found that the bubbles oxygenate the water behind the bubbles while it travels toward the top surface in the water pool. This system reduces the oxygen transfer efficiency as the diffuser r...

Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of th...

This paper presents the investigation of the macrostructure, microstructure, and solidification structure of two ferrous based materials produced by the LENS™ process. The material deposited and examined in this work was a SAE 4140 low alloy steel. The focus of this work is to (1) identify the solidification structure and measure the Dendritic Arm...

A wind energy has getting more attention due to its free-source, its nature of renewable energy, and free of carbon dioxide emission. As the wind map varies area to area, the wind energy collection strongly depends on the site. In order to maximize the amount of energy captured, an improved, low airspeed wind turbines are demanded to be designed. A...

The impact wrench driver is used to deliver increasing torque with time. In most applications, the torque required needs to be at a predetermined level. The present method of achieving this is based on the skill of operator. The operator ball parks the torque and later measures with a torque wrench, making any necessary adjustments. To achieve a mo...

This paper addresses a study of air bubble creation and contact angle effect on bubble size through an investigation by using computational fluid dynamic (CFD), which were validated to experimental results. Contact angle was also investigated for the air, water interface at a rubber surface, Teflon coated surfaces and polytetrafluoroethylene (PTFE)...

Most blades available for commercial-grade wind turbines incorporate a straight, span-wise profile and airfoil-shaped cross-sections. These blades are found to be very efficient at low and medium wind speeds compared with the potential energy that can be extracted. This paper explores the possibility of increasing the efficiency of the blades by mo...

Aeration, a unit process in which air and water are brought into intimate contact, is an extremely important step in the process of wastewater treatment. The two most common systems of aeration are subsurface and mechanical. A mechanical system agitates the wastewater by various means (e.g. paddles, blades, or propellers) to introduce air from the...

This paper discusses basic standing wave theory as it relates to thermoacoustics as well as the design, construction, and testing of a simple thermoacoustic engine based upon these principles. This paper covers the design, construction, and testing of a proof-of-concept engine to demonstrate the possibility of converting heat energy into mechanical...

The Paper Mill Project goal is to improve upon the uniform heating of a continuous paper sheet flowing across a heat source for the purpose of drying the paper. The project tests different porous media to achieve uniform heat distribution across the paper. Existing designs overheat the paper to overcome the uneven heat distribution caused by uneven...

The following report illustrates the design steps to complete the hammer drill efficiency project. The main goal of the project is to provide a mathematical relationship between the variables that make up the hammer drill. Once established these relations will allow the designer to predict the rate at which holes may be drilled. This will be accomp...

This paper presents the factors affecting air bubble size when air is injected through a perforated membrane into a water pool. Critical factors that govern the size of air bubbles are the air pressure and the flow rate as well as the hole size of the diffuser membrane. In order to have a better understanding of how bubble size can be affected and...

Turbomachinery industries are interested in using optimization procedures that enable to enhance compressor efficiency and wide operating ranges. Most of the design processes are focus on either in aerodynamics or structure. However, the compressor design is an integration between the aerodynamics and structure. This paper presents the recent devel...

In order to enhance the performance of a gas turbine and to maintain the blade material within operating temperature range, cooling channels are made within the blade materials that extract the heat. The walls of these cooling channels are usually enhanced with some sort of turbulence generators — ribs and dimples being the most common. While both...

The aerodynamics of a straight edged and a swept edged blade are investigated using a commercial CFD code. RANS equations with SST k-ω equation were utilized to study the flow separation along the blades span in a stall region. The analysis results will be used to provide inputs to future designs to improve and to enable better prediction of the st...

This paper addresses a study of air bubble creation and contact angle effect on bubble size through an investigation by using computational fluid dynamic (CFD), which were validated to experimental results. Contact angle was also investigated for the air, water interface at a rubber surface, Teflon coated surfaces and polytetrafluoroethylene (PTFE)...

Centrifugal compressors have widely applications in industrial gas compression processes. Limitations of installation and compressor package always request to modify the compressor geometry to fit certain constrains. Very often, the modifications of the scroll were performed to meet the space constrains. To meet the installation and package require...

The firing temperature in gas turbine relates itself directly to the power output and the efficiency of the turbine. The higher the firing (operating) temperatures, higher the wall temperature of blades. However, an increase in the firing temperature is limited by the first stage blade material properties. This is because the higher firing temperat...

Various external heat exchangers (EHE) are widely used in large-scale circulating fluidized bed (CFB) boilers. A new type of pneumatically controlled EHE was developed in this paper. The major feature of this EHE system was that the flow of solids to two heat transfer chambers could be controlled. Thereby the quantity of heat transfer of different...

The present paper is concerned with the numerical simulations of the turbulent flow and heat transfer in circular pipes using a low Reynolds number model for turbulence kinetic energy and its dissipation rate. Unlike the high Reynolds number turbulence models, the present solution procedure requires no special treatments near the pipe walls; i.e.,...

The present paper is concerned with the numerical computations of flow, heat transfer and chemical reactions in two-dimensional cylindrical gas reformers. The reformer is overlaid with a two-dimensional grid of nodes having 300 in the radial direction and 1000 nodes in the axial direction. The governing equations for momentum, mass continuity, ener...

The drying effectiveness is studied using a cloth. The forced air propane heater with an extended sheet metal duct was used to direct the hot air onto the moving cloth. The cloth was run using a 1 hp motor with an electronic controller. The motor also had a pulley system to reduce the speed. The outlet of the hot air duct was placed just below the...

Pollution by petroleum products is a source of volatile organic compounds in soil. Therefore, laboratory column venting experiments were completed in order to investigate the removal of a pure compound (toluene) and a mixture of two (toluene and n-heptane) and five (toluene, n-heptane, ethylbenzene, m-xylene and p-xylene) compounds. The choice of t...

A scroll is used to collect and transport swirling fluid produced by impeller and diffuser. Scroll or volute is one of the key components of centrifugal compressors. Design of the scroll not only impacts compressor efficiency but also influences operating range of the compressor. In this study, Navier-Stokes equations with both the zero-equation tu...

Recently there has been an increase in the demand for the utilization of clean renewable energy sources. This is a direct result of a rise in oil prices and an increased awareness of human induced climate change. Wind energy has been shown to be one of the most promising sources of renewable energy. With current technology, the low cost of wind ene...

A square cyclone separator with double inlets was developed for a new type Circulating Fluidized Bed (CFB) boiler arrangement scheme including two furnaces. Experiments on the performance and gas-solid flow recorded by a high-speed photography have been conducted in a cold test rig with a separator cross section 400mm×400mm. Experimental results in...

It is always one of the most challenging problems to control an underwater robotics due to the complex external forces in an underwater environment. It is difficult to obtain an ideal control performance using linear control technologies due to highly nonlinear properties of system. A valid method of linearization for nonlinear system is provided i...