Preliminary Evaluation of an Active Clearance Control System Concept

2005 ◽  
Author(s):  
Bruce Steinetz ◽  
Scott Lattime ◽  
Shawn Taylor ◽  
Jonathan DeCastro ◽  
Jay Oswald ◽  
...  
Keyword(s):  
Control System ◽  
Preliminary Evaluation ◽  
System Concept ◽  
Clearance Control

LM9000 Passive Clearance Control (PCC)

2020 ◽  
Author(s):  
Simone Marchetti ◽  
Duccio Nappini ◽  
Roberto De Prosperis ◽  
Paolo Di Sisto
Keyword(s):  
Control System ◽  
Low Pressure ◽  
Industrial Applications ◽  
Flow Path ◽  
Operating Conditions ◽  
Low Pressure Turbine ◽  
Power Turbine ◽  
Extensive Test ◽  
First Time ◽  
Clearance Control

Abstract This paper describes the design of the Free Power Turbine (FPT) of the LM9000, in particularly the design of its Passive Clearance Control (PCC) system. The LM9000 is the aero-derivative version of the GE90-115B jet engine. Its core engine has many common parts with the GE90; what differs is the booster (low pressure compressor) and the lower pressure turbine (LPT). The booster of the LM9000 is without fan because the engine is not used to provide thrust but torque only, subsequently it has a new flow path [5]. The LPT has instead been replaced by an intermediate pressure turbine (IPT) and by the FPT. The IPT drives the booster, while the FPT is a free low-pressure turbine designed for both power generation and mechanical drive industrial applications, including LNG production plants. Due to its different application, the LM9000 FPT flow path differs sensibly from the GE90 LPT, however as the GE90 it is provided of a clearance control system that cools the casing in order to reduce its radial deflection. It is not the first time that a clearance control system has been used in industrial applications; in GE aero-derivative power turbines is already present in the LM6000 and LMS100. Design constraints, system complexity, high environment variability because the PCC is located outside the GT, harsh environments and long periods of usage still make the design of this component challenging. The design of the PCC has been supported by extensive heat transfer and mechanical simulations. Each PCC component has been addressed with a dedicated life calculation and all the blade and seal clearances have been estimated for all the operating conditions of the engine. Simulations have been validated by an extensive test campaign performed on the first engine.

scholarly journals Development and Preliminary Evaluation of an Integrated Individual Nozzle Direct Injection and Carrier Flow Rate Control System for Pesticide Applications

2019 ◽  
Vol 62 (2) ◽  
pp. 505-514 ◽  
Author(s):  
Joe D. Luck ◽  
Scott A. Shearer ◽  
Michael P. Sama
Keyword(s):  
High Pressure ◽  
Control System ◽  
Direct Injection ◽  
Injection System ◽  
Preliminary Evaluation ◽  
Variable Flow ◽  
Carrier Flow ◽  
Duty Cycles ◽  
Nozzle Injection ◽  
Injection Frequency

Abstract. Direct injection systems for agricultural spray applications continue to present challenges in terms of commercialization and adoption by end users. Such systems have typically suffered from lag time and mixing uniformity issues, which have outweighed the potential benefits of keeping chemical and carrier separate or reducing improper tank-mixed concentration by eliminating operator measurements. The proposed system sought to combine high-pressure direct nozzle injection with an automated variable-flow nozzle to improve chemical mixing and response times. The specific objectives were to: (1) integrate a high-pressure direct nozzle injection system with variable-flow carrier control into a prototype for testing, (2) assess the chemical metering accuracy and proper mixing at different combinations of injection valve frequency and duty cycle along with chemical pressure, and (3) assess the ability of the control system to ensure proper chemical dilutions and concentrations in the nozzle effluent resulting from step changes in target application rates. Laboratory experiments were conducted using the combined system. Results of these experiments showed that the open-loop control of the injectors could provide a means of accurately metering the chemical concentrate into the carrier stream. Chemical injection rates could be achieved with an average error of 5.4% compared to the target rates. Injection at higher duty cycles resulted in less error in the chemical concentration predictions. Discrete Fourier transform analysis showed that the injection frequency was noticeable in the nozzle effluent when the injector was operated at 3.04 MPa and 5 Hz (particularly at lower duty cycles). Increasing the injection pressure and operating frequency to 5.87 MPa and 7 Hz, respectively, improved mixing, as the injection frequency component was no longer noticed in the effluent samples. The variable-flow nozzle was able to maintain appropriate carrier flow rates to achieve product label chemical concentrations. In one case, the maximum allowable concentrate was exceeded, although the nozzle was able to recover in 0.5 s. Steady-state errors ranged from 2.5% to 7.5% for chemical concentrations compared to the selected chemical to carrier ratio (0.03614). This test scenario represented an application rate of 4.68 L ha-1 with velocity increases from 4.0 to 7.1 m s-1 and decreases from 7.1 to 4.0 m s-1, which were typical of the example field application data. Keywords: Pesticides, Precision agriculture, Spraying equipment, Variable-rate application.

scholarly journals Development and Preliminary Evaluation of a New Bin Filler for Apple Harvesting and In-Field Sorting Machine

2017 ◽  
Vol 60 (6) ◽  
pp. 1839-1849 ◽  
Author(s):  
Zhao Zhang ◽  
Anand Kumar Pothula ◽  
Renfu Lu
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Mechanical System ◽  
Critical Role ◽  
Unit Cost ◽  
Preliminary Evaluation ◽  
Key Innovation ◽  
The Status ◽  
Arduino Microcontroller ◽  
Sorting System

Abstract. The bin filler, which is used for filling the fruit container or bin with apples coming from the sorting system, plays a critical role in the self-propelled apple harvest and in-field sorting (HIS) machine that is being developed in our laboratory. Two major technical challenges in developing the bin filler are limited space in the HIS machine and high throughput. A literature review showed that despite many different types of bin fillers currently available for in-field use, none of them is suitable for the HIS machine because of their large size, use of the bin rotating design concept, and high unit cost. Effort has thus been made on the development of new bin filling technology for use with the HIS machine. The new bin filler mainly consists of a mechanical system with a pinwheel design and an automatic control system. A key innovation in the mechanical system is the use of two foam rollers to catch freely falling apples, which has greatly simplified the bin filler design and also made the system compact and lower in cost. The control system is mainly composed of an onboard Arduino microcontroller and three sensors (one infrared sensor and two Hall effect sensors) to monitor and measure the status of apples filling the bin as well as the rotational speed of the pinwheel. A program was developed for the Arduino microcontroller to record and process the data from the sensors in real-time to achieve automatic control of the bin filling. Laboratory tests with ‘Gala’ apples demonstrated that 97% of apples that had been handled by the new bin filler were rated Extra Fancy grade, and its performance exceeded the industry’s requirement for bruising damage to apples. Keywords: Apples, Automatic control, Bin filling, Bruising, Harvest, Sensors, Sorting and grading.

A System Concept for an Advanced Vehicle Control System

Insight ◽  
2000 ◽  
Vol 3 (3) ◽  
pp. 15-20
Author(s):  
David E. Mackey ◽  
William F. Mackey ◽  
William F. Mackey
Keyword(s):  
Control System ◽  
Vehicle Control ◽  
System Concept

Innovative Measurement Techniques for a Cooled Turbine Casing Operating at Engine Representative Thermal Conditions

2014 ◽  
Author(s):  
Andrew G. Dann ◽  
Steve J. Thorpe ◽  
Leo V. Lewis ◽  
Peter Ireland
Keyword(s):  
Control System ◽  
Cooling System ◽  
Measurement Techniques ◽  
Axial Displacement ◽  
Tip Clearance ◽  
Test Facility ◽  
Uniform Heat Flux ◽  
Thermal Transients ◽  
Turbine Casing ◽  
Clearance Control

To optimize the efficiency of modern aero-gas turbine engines the turbine tip clearances must be tightly controlled so as to minimize leakage losses. In addition, the clearance control system must be able to respond with sufficient rapidity to engine thermal transients. One method of achieving turbine tip-clearance control is to manipulate the turbine casing temperature, and thereby radial growth, by convective cooling. The consequent clearance control system represents a particularly complex thermo-mechanical design problem. The current experimental study aims to simulate the heat loads to which the internal surfaces of the casing are typically exposed and to characterize the radial and axial displacement of the free-body casing under varying external cooling conditions. Importantly, the newly commissioned test facility allows a realistic assessment of the casing cooling impact on dimensional control, and also the rapid characterization and comparison of different concepts. The test facility comprises a model of a high-pressure/intermediate-pressure turbine casing with generic impingement cooling manifolds. A radiant heater is mounted within the casing model such that a near-uniform heat flux condition can be established on the casing wall inner surface. Extensive surface mounted thermocouples are welded to the casing wall to monitor variations in metal temperature. Radial and axial displacement of the casing is monitored using laser triangulation and linear variable differential transformer sensors. Experiments have been conducted over a range of heat load conditions and with engine representative levels of casing cooling applied. Importantly, the new test facility allows for the characterization of the casing cooling system as a whole.

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