Furthur development of the dynamic gas temperature measurement system

Candidate concepts capable of generating dynamic temperatures were identified and analyzed for use in verifying experimentally the frequency response of the dynamic gas temperature measurement system. A rotating wheel concept and one other concept will be selected for this purpose. Modifications to the data reduction code algorithms developed were identified and evaluated to reduce substantially the data reduction execution time. These modifications will be incorporated in a new data reduction program to be written in FORTRAN IV

Further development of the dynamic gas temperature measurement system

The objective of this effort was to experimentally verify a dynamic gas temperature measurement system in laboratory experiments. The dynamic gas temperature measurement system verification program is described. A brief description of the sensor geometry and construction is followed by a discussion of the probe heat transfer analysis and subsequent compensation method. The laboratory experiments are described and experimental results are discussed. Finally, directions for further investigation are given

Dynamic gas temperature measurement system

A gas temperature measurement system with compensated frequency response of 1 KHz and capability to operate in the exhaust of a gas turbine combustor was developed. Environmental guidelines for this measurement are presented, followed by a preliminary design of the selected measurement method. Transient thermal conduction effects were identified as important; a preliminary finite-element conduction model quantified the errors expected by neglecting conduction. A compensation method was developed to account for effects of conduction and convection. This method was verified in analog electrical simulations, and used to compensate dynamic temperature data from a laboratory combustor and a gas turbine engine. Detailed data compensations are presented. Analysis of error sources in the method were done to derive confidence levels for the compensated data

Further development of the dynamic gas temperature measurement system

Two experiments for verifying the frequency response of a previously-developed dynamic gas temperature measurement system were performed. In both experiments, fine-wire resistance temperature sensors were used as standards. The compensated dynamic temperature sensor data will be compared with the standards to verify the compensation method. The experiments are described in detail

Dynamic gas temperature measurement system, volume 1

A gas temperature measurement system with compensated frequency response of 1 kHz and capability to operate in the exhaust of a gas turbine engine combustor was developed. A review of available technologies which could attain this objective was done. The most promising method was identified as a two wire thermocouple, with a compensation method based on the responses of the two different diameter thermocouples to the fluctuating gas temperature field. In a detailed design of the probe, transient conduction effects were identified as significant. A compensation scheme was derived to include the effects of gas convection and wire conduction. The two wire thermocouple concept was tested in a laboratory burner exhaust to temperatures of about 3000 F and in a gas turbine engine to combustor exhaust temperatures of about 2400 F. Uncompensated and compensated waveforms and compensation spectra are presented

Further development of the dynamic gas temperature measurement system. Volume 1: Technical efforts

A compensated dynamic gas temperature thermocouple measurement method was experimentally verified. Dynamic gas temperature signals from a flow passing through a chopped-wheel signal generator and an atmospheric pressure laboratory burner were measured by the dynamic temperature sensor and other fast-response sensors. Compensated data from dynamic temperature sensor thermoelements were compared with fast-response sensors. Results from the two experiments are presented as time-dependent waveforms and spectral plots. Comparisons between compensated dynamic temperature sensor spectra and a commercially available optical fiber thermometer compensated spectra were made for the atmospheric burner experiment. Increases in precision of the measurement method require optimization of several factors, and directions for further work are identified

Late-season Corn Development and Frost Probabilities

Cool August temperatures across Iowa slow growing degree day (GDD) accumulations. In addition, Iowa’s late corn planting dates this year obviously impacted the crop as well. These two factors affect corn yield potential

Corn Crop Development and Conditions at the End of July 2012

To no one’s surprise, Iowa corn conditions declined throughout the month of July. Dry hot weather hammered the crop to the point where some crops were written off as unproductive several weeks ago and others are seemingly hanging by a thread. Some producers are salvaging what remains as silage. Nevertheless, some Iowa producers are quite satisfied with their crop’s potential. They are among the fortunate few perhaps with a bit better soils and more rain at critical periods. Undoubtedly, this group may also have an edge on management practices: excellent hybrid selection, less soil compaction, timely planting dates, better seed placement, uniform seedling emergence, optimum plant populations, top-notch weed control, wise insect and disease management, etc. This will be the year where the management differences among fields and producers - and their skills - will come to light

Root-lodged corn at or before silking

Several areas of Iowa last week experienced strong winds along with thunderstorms. Fortunately, these storms provided some much-needed moisture for kernel set on corn, but the winds in some places were strong enough to root lodge corn. Corn affected ranged from just silked (R1), the blister stage (R2), to some in the milk stage (R3). In areas with corn not yet tasseled, greensnap occurred. I\u27ll discuss greensnap another time. For this article, I\u27ll discuss the following: Why did some plants root lodge and others didn\u27t? How will root lodging affect yield? And what can we learn that will reduce root lodging in the future

Corn and Dry Soils at Planting, Looking Ahead to 2012—Part I: Yield prediction with dry conditions at planting

Dry conditions persist in many parts of Iowa. As of Jan. 30, modeled volumetric root-zone soil water in the northwestern half of the state was one-third or less (see Mesonet map). Elwynn Taylor, Iowa State University Extension and Outreach climatologist, indicates there is some probability that these dry conditions will persist