High temperature imaging dynamic measurement techniques under harsh experimental environment

The temperature measurement of a very high temperature core melt is of importance in LAVA (lower-plenum Arrested Vessel Attack) experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The existing temperature measurement techniques have some problems, where the thermocouple, one of the contact methods, is restricted to under 2000°C, and the infrared thermometry, one of the non-contact methods, is unable to measure an internal temperature and very sensitive to the interference from reacted gases. So, in order to solve these problems, the delay time of ultrasonic wavelets due to high temperature is suggested. One of the key initial conditions to be measured in LAVA is the initial corium melt temperature. To measure it, the LAVA measurement group has developed several kinds of UTS’s. As a first stage, a molten material temperature was measured up to 2314°C. Also, the optimization design of the UTS (ultrasonic temperature sensor) with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in this paper and the efficiency of the developed system are certified by performing experiments.

Download Full-text

Blade by Blade Tip Clearance Measurement

International Journal of Rotating Machinery ◽

10.1155/2011/516128 ◽

2011 ◽

Vol 2011 ◽

pp. 1-13 ◽

Cited By ~ 19

Author(s):

A. G. Sheard

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Measurement System ◽

Measurement Techniques ◽

Tip Clearance ◽

Initial Development ◽

Real World Applications ◽

Blade Tip ◽

Capacitance Probe ◽

Blade Tip Clearance

This paper describes a capacitance-based tip clearance measurement system which engineers have used in the most demanding turbine test applications. The capacitance probe has survived extended use in a major European gas turbine manufacturer's high-temperature demonstrator unit, where it functioned reliably at a turbine entry temperature in excess of 1800 degrees Kelvin. This paper explores blade by blade tip clearance measurement techniques and examines probe performance under laboratory conditions in support of high-temperature installations. The paper outlines the blade by blade tip clearance measurement technique and describes the experimental facility used to study tip clearance measurement. The paper also fully describes the method used to calibrate the measurement system in order to ascertain measurement accuracy. The paper clarifies how the practical problems were overcome associated with making blade by blade tip clearance measurements in both compressor and turbine environments. Since its initial development, gas turbine development programmes have routinely used the clearance measurement system. The inherent robustness of the system has resulted in reliable in-service measurement of clearance in real world applications.

Download Full-text

Static and Dynamic Pressure Measurements With Temperature Correction Using High Temperature Optical Pressure Sensors

Volume 3: Controls, Diagnostics and Instrumentation; Cycle Innovations; Marine ◽

10.1115/gt2010-22904 ◽

2010 ◽

Author(s):

A. P. R. Harpin

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Dynamic Range ◽

Dynamic Pressure ◽

Measurement Techniques ◽

Pressure Sensors ◽

Real Life ◽

Temperature Correction ◽

Harsh Environments ◽

Wide Range

We describe our range of high temperature (1100°C) pressure sensors capable of measuring both static pressures of several Bar as required by gas turbine and jet engines, and measuring dynamic pressure fluctuations with a total dynamic range of in excess of 100000. This is achieved by a combination of rugged sensor design and our proprietary optical interrogator. This allows operation in harsh environments, EMI immunity, and simultaneous interrogation of not only static and dynamic pressure, but also the temperature of the sensor. This allows the sensor to maintain high accuracy over a wide range of operating temperatures. To date sensors have not been able to offer operation temperatures this high whilst enabling accurate dynamic pressure readings at the locations required. Also the static pressure cannot be retrieved simultaneously in real time from the same sensor. Also the temperature coefficient of the sensor has to be taken into account by measuring the temperature the sensor is operating at. Oxsensis has addressed these issues and we will present results showing dynamic pressure and temperature and explain how we can measure the temperature of the sensor with our interrogation schemes. We will describe the form of the sensor and the test data confirming its suitability for harsh environments. We will also explain the optical interrogator performance and present simulated results. The interrogator may be realised by a slave cavity or preferably on an integrated optical platform. As these sensors are intended for hostile gas turbine and aerospace environments, we will also present data from real life engine trials that we have performed, and compare the data we obtained with existing measurement techniques. Tests on a combustor rig have tested the sensor up to 1000°C, demonstrating that using our sensors in an engine at these temperatures is a realistic prospect. We believe that the ruggedness and performance of these sensors together with our complimentary interrogators mean that they are of significant interest to instrumentation of gas turbine engines and in the future the development of sophisticated engine feedback and emission control schemes, both in land based and aerospace environments.

Download Full-text

Assessment of Weld Overlays in Cladded Piping Systems With Varied Thicknesses

Volume 4: Materials Technology ◽

10.1115/omae2019-96348 ◽

2019 ◽

Author(s):

Bridget Kogo ◽

Bin Wang ◽

Luiz Wrobel ◽

Mahmoud Chizari

Keyword(s):

Computer Simulation ◽

Stainless Steel ◽

High Temperature ◽

Numerical Methods ◽

Close Agreement ◽

Dissimilar Materials ◽

Dynamic Measurement ◽

Piping Systems ◽

Simulation Results ◽

Weld Overlays

Abstract This paper continues the research previously done by authors on computer simulation of the dissimilar welded joints with varying clad thicknesses using numerical methods. For different cladding thicknesses comprising of stainless steel and mild steel, stress curves have been generated. The welding of the two dissimilar materials has been carried out in-house with the aid of a tungsten arc weld with dynamic measurement of the temperature profile in vicinity of the welding track using high temperature thermocouples. Comparison of the experimentally measured stresses from literature versus the simulation results shows close agreement.

Download Full-text