Lee Langston

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Verified

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• PhD
• Professor Emeritus at University of Connecticut

The event of the last 747 off the production line was marked by many retrospectives in the media. Virtually every one of them described an uneventful engineering success story. In actuality, the jetliner was cutting-edge technology when it was first developed and in need of some solid, thinking-on-your-feet engineering to make it fly.

Fueling gas turbines with hydrogen was a path not taken by early innovators. And for good reasons: Hydrogen atoms are so reactive that very little molecular hydrogen is available. Hydrocarbon fuels, such as methane, kerosene, and gasoline, became the energy source of choice for the technology. But the need to reduce carbon emissions has revived int...

The gas turbine industry took some unprecedented hits in 2020. And some sectors, such as the jet engine market, may take some time to recover. But new technologies, such as hydrogen burning turbines, give reason for hope.

In the family of heat engines, the gas turbine is unique in that it is used to produce two different kinds of useful power. By converting combusted fuel heat into work, a gas turbine engine can produce external shaft power (e.g., to drive a connected electric generator) or jet power (e.g., as a jet engine, to produce thrust forces to propel an airc...

The gas turbine industry has had many successes, but this past year it has been dogged by the specter of two great mistakes—one that occurred, and another that is being threatened. Many groups are pushing for the immediate elimination of natural gas as a fuel source, and some jurisdictions have begun to ban new residential gas hook-ups. This study...

As prime movers go, gas turbines are virtually brand new, compared to, say, wind and water turbines which have been around for millennia. But they have also reached a considerable level of maturity. Gas turbines now dominate both the world’s aircraft propulsion and a good portion of electric power generation. The fortunes of the industry are not un...

An updated report is given on the University of Connecticut’s gas turbine combined heat and power plant, now in operation for 13 years after its start in 2006. It has supplied the Storrs Campus with all of its electricity, heating and cooling needs, using three gas turbines that are the heart of the CHP plant. In addition to saving more than $180 m...

Hydrogen, reacting with oxygen, is a very energetic, non-polluting fuel. Can it be used as a fuel for gas turbines? Two successful and significant examples of its use are reviewed. Surplus renewable electrical energy from solar and wind could be used for electrolysis of water to produce hydrogen to power gas turbine power plants. Serving as a means...

A major factor in the continued domination of turbofan engines for economic airline propulsion, is the ability to increase bypass ratios. However, increasing fan diameters to go to ever higher bypass ratios increases nacelle weight, aerodynamic drag and duct losses. By eliminating the need for a fan duct, open rotor engines can effectively in-creas...

The mounting of a jet engine under the wing of an airliner can be a daunting task for turbofan engineers. Thrust forces generated by gas path momentum flow changes in a jet engine are transmitted by pressure (and friction) forces on stators and struts attached to the engine case. Case engine mounts then transmit the thrust forces (as high as 100,00...

How to get public articles by Lee S. Langston

The promises of increased efficiency, simplicity, and high power density are driving the current research focus on rotating detonation engines (RDEs). An engine that uses detonation rather than deflagration could have some key advantages. If harnessed in a gas turbine or rocket, detonation could reduce the need for some expensive hardware, lighten...

This article provides the latest trends in the gas turbines market and their future outlook. The last three years of operation have generated more profit for the commercial airline industry than the previous 30 years combined. That money has led to new orders for commercial aircraft and as a result, production of commercial aviation gas turbines is...

This article discusses the significance of bird ingestion in jet engines. Bird strikes occur at various aircraft locations, however, usually inflict most damage to the engines. Airplane damage and effect on flight from bird strikes are closely correlated to kinetic energy, derived from the mass (determined by the bird species) and the velocity of c...

This article presents three different gas turbine phenomena and design cases. The sketch in the article shows a schematic of a combined cycle powerplant consisting of a Brayton cycle (gas turbine) whose exhaust provides energy to a Rankine cycle (steam turbine). Frequently, one can use simple but exact one-dimensional (1D) heat conduction solutions...

This article discusses how advancement in turbine cooling techniques has helped enhancing the performance and endurance of turbines. Gas turbine thermal efficiencies increase with higher temperatures of the gas flow exiting the combustor and entering the work-producing component—the turbine. The fundamental aim of a turbine heat transfer designer i...

This article reviews the development of geared turbofan (GTF) engines. GTF engines have a hub-mounted epicyclic gearbox that drives the front-mounted fan at lower rotational speeds than the engine turbine section that powers the fan. The turbine driving the fan is most efficient at high-rotational speeds. The fan operates most efficiently and creat...

This article highlights technological performance improvements in the gas turbine industry and its likely future course. While the outlook for commercial aviation gas turbines is bright, the non-aviation segment is decidedly clouded. While analysts have focused on the growing demand for electricity worldwide, the average output of each individual g...

This article elaborates various challenges presented by stall and surge to the gas turbine research community and jet engine designers. The article also presents several examples of stall and surge faced by the pilots. Stall and surge emerge from basic physics: the behavior of the boundary layer on the compressor blades and stators; however, curren...

This article explains research and development in the field of gas turbine power plants. Natural gas fueled gas turbines driving generators are proving to be the most versatile and effective energy converter in the engineer's arsenal of prime movers. Continued research and development are making these gas turbine power plants even more effective, f...

This article discusses various fields where gas turbines can play a vital role. Building engines for commercial jetliners is the largest market segment for the gas turbine industry; however, it is far from being the only one. One 2015 military gas turbine program of note was the announcement of an U.S. Air Force competition for an innovative design...

This article discusses various aspects and need for gas turbine disc resurrection. Depending on the record keeping system used by the government, airlines, OEMs, and users, gas turbine discs are retired before they reach a critical state that might lead to their failure. Experts have reviewed current approaches to gas turbine life management. They...

This article presents an overview of use, advantages, and challenges related to ceramic gas turbines. The research shows that if these ceramic parts perform as promised, both operationally and economically, it could radically alter the jet engine industry. The promise of ceramics is that by taking advantage of their lower weight and superior high t...

This article highlights various aspects of a new gas turbine shaft seal called the pressure activated leaf seal (PALS). The paper in detail discusses the architecture and working of a gas turbine seal. PALS is designed to use changing pressure drop forces across the seal to eliminate rub. The seal elements stay clear of the rotor seal surface durin...

This article explains how combined cycle gas turbine (CCGT) power plants can help in reducing greenhouse gas from the atmosphere. In the last 25 years, the development and deployment of CCGT power plants represent a technology breakthrough in efficient energy conversion, and in the reduction of greenhouse gas production. Existing gas turbine CCGT t...

This article presents thoughts and experiences of R. Tom Sawyer, founder of International Gas Turbine Institute’s (IGTI) Turbo Expo. Sawyer founded gas turbine technical institute, and set its course for its first four decades, during which time the gas turbine itself, became one of the world’s most useful energy converters. Sawyer joined the Ameri...

This study analyses the changes that gas turbines have brought in the field of air and land transport and technology. The worldwide production of gas turbines includes the commercial and military aviation markets, as well as non-aviation markets for electrical generation, marine applications, and mechanical power. In recent years, gas turbine combi...

This article discusses various features of supercharged gas turbine and supercharged analysis. One 400 MW supercharged gas turbine power plant variant analysed by Wettstein yielded a predicted thermal efficiency of 60 percent, rivaling current combined cycle values. The supercharged gas turbine power plant proposed by Wettstein is a semi-closed (SC...

This article presents success and failure stories of turbo expo. For the first three score years, the International Gas Turbine Institute’s (IGTI) Turbo Expo has been the pre-eminent gas turbine conference. The IGTI Turbo Expo in June 2015 will be the 60th gathering—surely a record in longevity and vitality for a single technology conference. The i...

Large gas turbines used in electric power plants are using supersized single-crystal blades and vanes for both corrosion resistance and increased temperature capability, which add to efficiency. General Electric's 9H turbine, a 50-hertz combined-cycle gas turbine s one of the world's largest. The first model, 9H, weighing 367,900 kilograms, uses si...

This GE study represents the first open literature report of plasma actuators actually used on gas turbine blading at representative engine flow conditions. The exact mechanisms of interaction between weakly ionized gas and neutral air are still under study; however, the collisional processes between them are responsible for the momentum transfer c...

This article discusses the use of turbine single-crystal blades in gas turbines. Single-crystal turbine blades were first used in military engines on Pratt’s F100 engine, which powered the F16 and F15 fighter aircrafts. Their first commercial use was on P&WA’s JT9D-7R4 engine, which received FAA certification in 1982, powering Boeing’s 767 and the...

This article focuses on the use of gas turbines for electrical power, mechanical drive, and marine applications. Marine gas turbines are used to generate electrical power for propulsion and shipboard use. Combined-cycle electric power plants, made possible by the gas turbine, continue to grow in size and unmatched thermal efficiency. These plants c...

This article explains various technical aspects of the boundary layer ingestion (BLI) concept. Using BLI, airliner designs featuring close-coupled, rear-mounted turbofans are being considered, with a fuselage sculpted to sweep a large part of the fuselage boundary layer into engine inlets for reduced fuel consumption. With an engine array fuselage-...

The article describes how the pebble-bed reactor can make fission energy safe in the US. At present, about 20 percent of the electricity in the United States is generated by 104 nuclear power plants across the country, making it the leading nation in total installed nuclear capacity. There are now 440 reactors in operation around the world, providi...

This article presents an overview of the current state of dealing with jet engine bird ingestion. At Turbo Expo ‘13 in San Antonio, Dr. Aspi Wadia of GE Aviation and Dr. Lee S. Langston (author of this paper) co-chaired a three-hour panel, ‘Jet Engine Bird Ingestion – Current Issues and Ways Forward.’ The leadoff panelist was Capt. Paul Eschenfelde...

This article presents a study of Pratt & Whitney’s J58, till date the best and high-powered engine for manufacturing lessons required for the development of F35 Joint Strike Fighter. The J58 Blackbird engine is a variable cycle engine, a turbojet/ramjet combined-cycle engine. It is a conventional afterburning turbojet for take-off and transonic fli...

This article focuses on various technical and functional aspects of detonation gas turbines. Detonation combustion involves a supersonic flow, with the chemical reaction front accelerating, driving a shock wave system in its advancement. In the 1990s, detonation-based power concepts began with pulse detonation engines (PDEs), and have now moved int...

This article focuses on studying blade tip clearance phenomena. It is important to realize that to be freely turning, a blade (or a cantilevered stator) must have a clearance gap between its tip and the engine casing (or hub). Such clearances introduce aerodynamic losses, decreasing gas turbine efficiency. Tip leakage losses in compressors can be s...

Turbines have been around for a long time. The name comes from the Latin turbo, meaning vortex. Gas turbine or jet engine thrust power is equal to the momentum increase in the mass flow engine inlet to exit, multiplied by the flight velocity. The actual thrust force produced in the engine is the summation of all the axial components of pressure for...

This article explores the advantages of gas turbines in the marine industry. Marine gas turbines, which are designed specifically for use on ships, have long been one of the segments of the gas turbine market. One advantage that gas turbines have over conventional marine diesels is volume. Gas turbines are the prime movers for the modern combined c...

This paper presents a review of gas turbines and Honeywell, a company based in Phoenix, history. The article through the review and historical analysis intends to provide perspective on the status of geared fan engines. The addition of a fan to a jet engine, first proposed by Frank Whittle, one of the inventors of the jet engine, increases thrust a...

This article presents a study on new electric power gas turbines and the advent of shale natural gas, which now are upending electrical energy markets. Energy Information Administration (EIA) results show that total electrical production cost for a conventional coal plant would be 9.8 cents/kWh, while a conventional natural gas fueled gas turbine c...

The first jet engine-powered aircraft flight and the first electric power produced by a land-based gas turbine both occurred in 1939, making the gas turbine one of the youngest energy conversion devices. A gas turbine consists of a rotating assembly of a compressor to draw in a gas (usually air) and a turbine to extract power from the gas flow. Ene...

This article talks about evolving technologies in making efficient gears for different auto engines. Gears are integral to a new engine that has the potential to change commercial aviation. Pratt & Whitney’s geared turbofan (GTF) jet engine will have significantly better fuel economy and much quieter operation. The P&W GTF combines existing jet eng...

This article discusses how incidents of bird strikes with jet engines can be avoided. According to a US Department of Transportation report, bird strikes have steadily and dramatically increased from 1770 reported in 1990 to 9840 in 2011, representing a fivefold increase in 20 years. The rise in strikes, as in other parts of the world, is due in pa...

This article describes the functioning of the gas turbine cogeneration power plant at the University of Connecticut (UConn) in Storrs. This 25-MW power plant serves the 18,000 students’ campus. It has been in operation since 2006 and is expected to save the University $180M in energy costs over its 40-year design life. The heart of the UConn cogene...

This article explores the new developments in the field of gas turbines and the recent progress that has been made in the industry. The gas turbine industry has had its ups and downs over the past 20 years, but the production of engines for commercial aircraft has become the source for most of its growth of late. Pratt & Whitney’s recent introducti...

This article describes the lucrative market for single-aisle narrow-body (SANB) commercial aircraft for the next 20 years. The SANB market has been the most lucrative for engine manufacturers. Boeing’s 737 and Airbus’s A320 families are powered by twin 30,000 pounds-thrust engines from CFM International or from International Aero Engines number in...

This article presents an overview of the history of International Gas Turbine Institute (IGTI). The IGTI gas turbine conference has been ASME's leading international technical meeting from its very beginning. The annual meeting is held in North America and in Europe on alternate years. Currently, more than half of the papers presented are from non-...

This article presents an overview of a pebble bed modular reactor (PBMR) power plant. A PBMR power plant is a gas turbine nuclear power plant that completely eliminates the possibility of a devastating loss-of-coolant accident. In a PBMR power plant, uranium dioxide nuclear fuel, coated with mass diffusion and radioactive fission product containmen...

This article explores the increasing use of natural gas in different turbine industries and in turn creating an efficient electrical system. All indications are that the aviation market will be good for gas turbine production as airlines and the military replace old equipment and expanding economies such as China and India increase their air travel...

The successful resolution of ovalization problems encountered in mounting the JT9D to the first Boeing 747s has provided guidance for future installations of large fan commercial jet engines. Pratt & Whitney Aircraft manufactured over 90 percent of the engines used in commercial aircraft. These included engines such as the JT3D on Boeing's 720 and...

This article discusses some specific incidents of uncontained jet engine failures. Such incidents usually involve the failure and disintegration of a rotating disc associated with the fan, compressor, or turbine of the gas turbine. Armed with enormous rotational kinetic energy, the disintegrated parts of a failed disk and its blading can become dan...

This article presents an overview of gas turbine combined cycle (CCGT) power plants. Modern CCGT power plants are producing electric power as high as half a gigawatt with thermal efficiencies approaching the 60% mark. In a CCGT power plant, the gas turbine is the key player, driving an electrical generator. Heat from the hot gas turbine exhaust is...

This article discusses ongoing research in the area of turbofans used in jet engines. P&W’s gear facilities in Middletown Connecticut have been developing the fan gearbox over a period of 20 years. The company has a long history of gearbox experience associated with their very popular turboprop gas turbines at Pratt & Whitney Canada. Field tests ha...

The eruption of volcanoes usually results in the cancellations of flights such as the eruption of Eyjafjallajökull blocked airline traffic into and out of some northern European airports. One of such encounters occurred on June 24, 1982, when British Airways Flight 9, a Boeing 747-200, with four Rolls-Royce RB-211 jet engines, passed over the islan...

The data provided by Forecast International (FI), Newtown, Conn., US, revealed that the demand for gas turbines continued to increase despite facing the challenge of economic recession. The data were gathered from aviation and non-aviation gas turbine markets that played a key role in the sector's continuous growth and development. Bill Schmalzer,...

This article presents an overview of the world’s very first industrial gas turbine, which started operation in the Swiss city of Neuchâtel, in 1939. This 4-MWe machine is now on display in a special museum on the grounds of Alstom in Birr village. The museum is housed in an attractive glassed-in building, adjacent to the rotor plant. The gas turbin...

Getting the right pitch to turbo machinery blading is key to efficiency and successful operation of gas turbines. Controlling the pitch of the blades can keep these turbomachines operating at peak efficiency as the fluid environment in which these blades turn or the amount of power to be added or extracted can change. Propeller blade pitch adjustme...

To further the understanding of secondary flow loss, a set of surface measurements are presented for a planar turbine cascade tested at low Mach number (0.23) and at an inlet axial chord Reynolds number of 5.9 × 105 . The endwall and airfoil surface measurements are of shear stress, limiting streamline direction, and static pressure. An oil film in...

An overview of the gas turbine industry for 2008 revealed that it continued to grow significantly with increased sales and better returns. It was revealed that companies continued to devote more resources to improve the performance of gas turbines, resulting in significant growth of the industry during the year. Advanced turbines were able to perfo...

New pressure and skin friction measurements on a cylinder were made and compared with analytical and computational modeling. The measurements were made in what we call the stagnation region, such as exists on the leading edge of a turbine airfoil. The new skin friction measurements were made with an oil film interferometry technique that has been u...

The focus of this paper is on the fluid mechanics and heat transfer at the stagnation flow region at the leading edge of a turbine cascade airfoil. The fluid mechanics analysis presented is based on the exact solution to the Navier-Stokes equation of Hiemenz for a plane stagnating laminar flow. The heat transfer analysis is based on Hiemenz flow an...

Gas turbine production, a $30 billion industry, a major contributor of commercial and military aviation, and the most important and versatile energy-converting business has experienced continued developments, landmarks, and breakthroughs in 2007. The total worldwide value of production for gas turbines for 2007 was $32.3 billion, compared to an ave...

The flow near the leading edge stagnation-line of a plane turbine cascade airfoil is analyzed using measurements, analytical modeling, and computational fluid dynamics (CFD) modeling. New measurements of skin friction and pressure indicate that the aerodynamics of the leading edge are well described by an exact analytical solution for stagnation-po...

South Africa is going to design a new reactor, pebble bed modular reactor (PBMR), that can revolutionize the nuclear power. The pebble bed modular reactor is a powerful plant design that uses heat from fission to fuel a gas turbine to generate electricity. The PBMR will have a gas turbine-driven electrical generator, which will convert some 41 perc...

This article illustrates capabilities of gas turbines to be able to work in extremely elevated temperatures. The turbine airfoils in the new F135 jet engine that powers the Joint Strike Fighter (JSF) Lightning II are capable of operating at these extreme temperatures. The F135 gas turbine is the first production jet engine in this new 3,600°F class...

The efforts made by author to build a cogeneration plant at the University of Connecticut (UConn) are presented. The author is a professor of mechanical engineering at the UConn and he wrote a letter to the president of the university for the plant. He outlined a plan to build the plant for combined generation of heat and power. The power generated...

The University of Connecticut is focusing on cogeneration, also called combined heat and power. It is the production of more than one useful form of energy—both heat and electric power—from a single energy source, such as the burning of natural gas or some other fuel. The cogeneration plant has been designed to blend seamlessly into the campus land...

Researchers and designers are continuously making efforts to enhance the performance of gas turbines the make them the premier energy conversion device and capable of being used in locomotives. Gas turbines are getting popularity both in aviation and nonaviation applications. The advantage of clean-burning gas turbine plants, thermal efficiency app...

The complex three-dimensional fluid flow on the endwall in an axial flow turbine blade or vane passage has been extensively investigated and reported on in turbomachinery literature. The aerodynamic loss producing mechanisms associated with the endwall flow are still not fully understood or quantitatively predictable. To better quantify wall fricti...

The use of single-crystal turbine blades by the gas turbine manufacturer is discussed. The unmatched resistance of single crystal to high-temperature creep and fatigue have helped to advance the performance and durability of modern gas turbines. The making of a single-crystal turbine airfoil starts the same as a direction solidification airfoil, wi...

Experimental results are presented which provide mass averaged total pressure loss coefficient measurements for three different turbine airfoil leading edge configurations. A baseline (Langston) configuration, a leading edge bulb, and a leading edge fillet were tested in a large-scale, low aspect ratio, high turning linear cascade. Results show tha...

Experimental results are presented which provide area-averaged total pressure loss coefficient measurements for four different turbine airfoil leading edge configurations. A baseline (Langston) configuration, two leading edge bulbs, and a leading edge fillet were tested in a large-scale, low aspect ratio, high turning linear cascade. Results show t...

A bubble describes something that lacks firmness, solidity, or reality. In its worse sense, it can be applied to a delusive commercial or financial scheme, such ass the recent dot-com hysteria. However, the market is rock-solid, with demonstrated long-term growth, subject to temporary divergences from an overall upward trend. To support this "anti-...

This article focuses on gas turbines that were produced in 2001 spanning a wide range of capacities. As the engineer's most versatile energy converters, gas turbines producing thrust power continued in 2001 to propel most of the world's aircraft, both military and commercial. The largest commercial jet engines today can produce as much as 120,000 p...

An important problem that arises in the design and the performance of axial flow turbines is the understanding, analysis, prediction and control of secondary flows. Sieverding has given a review of secondary flow literature, covering up to 1985. In this paper a brief review of pre-1985 work is given, and then a survey of open literature secondary f...

A numerical model was developed to simulate transient performance of a heat pipe turbine vane under typical gas turbine engine conditions. Curvilinear coordinates were used to describe the three-dimensional wall and wick heat conduction coupled with the quasi-one-dimensional vapor flow. A unique numerical procedure including two iterative estimate-...

This work investigates the effects of various parameters (geometric dimensions, working fluid, external heating and cooling conditions) on heat transfer performance of the heat pipe turbine vane. This parametric study is based on a numerical model which includes an one-dimensional vapor flow and a three-dimensional wall heat conduction. Heat transf...

In a fluid flow field where velocities are measured or numerically calculated, the vorticity value at a point in the field is usually estimated by approximating partial derivatives of velocity by ratios of velocity differences and spatial differences. This paper presents an alternate approach to estimate vorticity at the point in the fluid, based o...

Electromagnetic (EM) flow meters are used to measure volume flow rates of electrically conductive fluids (e.g., low magnetic Reynolds number flows of seawater, milk, etc.) in pipe flows. The possibility of using a modified form of EM flow meter to nonobtrusively measure boundary-layer flow characteristics is analytically investigated in this paper....

The iceformation design method was used to reduce the drag of a juncture between a cylinder and flat endwall. Ice was formed on a subfreezing flat endwall in a warmer laminar water flow. The ice shape was influenced by and altered the three-dimensional separated boundary layer and the cylinder wake. Preliminary experiments were used to indicate con...

A velocimeter for measuring the velocity field characteristics of a conductive fluid moving over a surface is provided. A magnet has a central axis that is aligned with a direction of fluid movement of interest such that a plurality of magnetic flux lines extend generally normal from the surface. A plurality of electrode pairs provide electrical ou...

This paper reports on the experimental description of the three-dimensional horseshoe vortex system occurring at the base of two cylinder mounted side by side on an endwall. The spacing between the two cylinders is adjusted to generate a family of viscous flows. Flow visualization performed in a water tunnel provides a qualitative understanding of...

This paper reports on the experimental description of flow past two cylinders that stand side by side on an endwall. Flow visualization performed in a water tunnel provides a qualitative understanding of the three-dimensional flow over a range of control variables. Limiting streamline flow visualization shows the location of the three-dimensional s...