scholarly journals Melt-layer thickness measurements during crushing experiments on fresh-water ice

1994 ◽  
Vol 40 (134) ◽  
pp. 119-124 ◽  
Author(s):  
R.E. Gagnon

AbstractA stainless-steel platen, with a centrally located pressure sensor on the front face, has been used to crush mono-crystalline, bubble-free fresh-water ice samples. Two electrical conductors, located on the face of the pressure sensor, were connected to a bridge circuit so that the presence of liquid between the two conductors could be detected and its thickness measured. Video records of the ice/ steel contact zone during crushing were obtained by mounting samples on a thick Plexiglas plate which permitted viewing through the specimen to the ice/steel interface. Total load and pressure records exhibited a sawtooth pattern due to the compliance of the ice and the testing apparatus, and spalling of ice from the contact zone. When the region of contact was in the vicinity of the pressure transducer, liquid was detected and peaks occurred in the liquid sensor output when load drops occurred. Contact between the platen and the ice consisted of low pressure zones of highly damaged crushed and/or refrozen ice, opaque in appearance, and transparent, high-pressure regions of relatively undamaged ice. Upper limits for the liquid-layer thickness on the high-pressure undamaged ice were ~3 µm on the ascending sides of the sawteeth in the load records and ~ 21 µ on the sharp descending sides.

1994 ◽  
Vol 40 (134) ◽  
pp. 119-124
Author(s):  
R.E. Gagnon

AbstractA stainless-steel platen, with a centrally located pressure sensor on the front face, has been used to crush mono-crystalline, bubble-free fresh-water ice samples. Two electrical conductors, located on the face of the pressure sensor, were connected to a bridge circuit so that the presence of liquid between the two conductors could be detected and its thickness measured. Video records of the ice/ steel contact zone during crushing were obtained by mounting samples on a thick Plexiglas plate which permitted viewing through the specimen to the ice/steel interface. Total load and pressure records exhibited a sawtooth pattern due to the compliance of the ice and the testing apparatus, and spalling of ice from the contact zone. When the region of contact was in the vicinity of the pressure transducer, liquid was detected and peaks occurred in the liquid sensor output when load drops occurred. Contact between the platen and the ice consisted of low pressure zones of highly damaged crushed and/or refrozen ice, opaque in appearance, and transparent, high-pressure regions of relatively undamaged ice. Upper limits for the liquid-layer thickness on the high-pressure undamaged ice were ~3 µm on the ascending sides of the sawteeth in the load records and ~ 21 µ on the sharp descending sides.


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4419
Author(s):  
Ting Li ◽  
Haiping Shang ◽  
Weibing Wang

A pressure sensor in the range of 0–120 MPa with a square diaphragm was designed and fabricated, which was isolated by the oil-filled package. The nonlinearity of the device without circuit compensation is better than 0.4%, and the accuracy is 0.43%. This sensor model was simulated by ANSYS software. Based on this model, we simulated the output voltage and nonlinearity when piezoresistors locations change. The simulation results showed that as the stress of the longitudinal resistor (RL) was increased compared to the transverse resistor (RT), the nonlinear error of the pressure sensor would first decrease to about 0 and then increase. The theoretical calculation and mathematical fitting were given to this phenomenon. Based on this discovery, a method for optimizing the nonlinearity of high-pressure sensors while ensuring the maximum sensitivity was proposed. In the simulation, the output of the optimized model had a significant improvement over the original model, and the nonlinear error significantly decreased from 0.106% to 0.0000713%.


2020 ◽  
pp. 1-4
Author(s):  
Andrii Murdza ◽  
Aleksey Marchenko ◽  
Erland M. Schulson ◽  
Carl E. Renshaw

Abstract Further to systematic experiments on the flexural strength of laboratory-grown, fresh water ice loaded cyclically, this paper describes results from new experiments of the same kind on lake ice harvested in Svalbard. The experiments were conducted at −12 °C, 0.1 Hz frequency and outer-fiber stress in the range from ~ 0.1 to ~ 0.7 MPa. The results suggest that the flexural strength increases linearly with stress amplitude, similar to the behavior of laboratory-grown ice.


1962 ◽  
Vol 4 (31) ◽  
pp. 25-52 ◽  
Author(s):  
W. F. Weeks

AbstractTo resolve some of the factors causing strength variation in natural sea ice, fresh water and five different NaCl–H2O solutions were frozen in a tank designed to simulate the one-dimensional cooling of natural bodies of water. The resulting ice was structurally similar to lake and sea ice. The salinity of the salt ice varied from 1‰ to 22‰. Tables of brine volumes and densities were computed for these salinities in the temperature range 0° to −35° C. The ring-tensile strength σ of fresh-water ice was found to be essentially temperature independent from −10° to −30°C., with an average value of 29.6±8.5 kg./cm.2at −10° C. The strength of salt ice at temperatures above the eutectic point (–21.2° C.) significantly decreases with brine volumev;. The σ–axis intercept of this line is comparable to the a values determined for fresh ice indicating that there is little, if any, difference in stress concentration between sea and lake ice as a result of the presence of brine pockets. The strength of ice containing NaCl.2H2O is slightly less than the strength of freshwater ice and is independent of the volume of solid salt and the ice temperature. No evidence was found for the existence of either phase or geometric hysteresis in NaCl ice. The strength of ice at sub-eutectic temperatures, however, is decreased appreciably if the ice has been subjected to temperatures above the eutectic point; this is the result of the redistribution of brine during the warm-temperature period. Short-term cooling produces an appreciable (20 per cent) decrease in strength, in fresh-water and NaCl.2H2O ice. The present results are compared with tests on natural sea ice and it is suggested that the strength of freshwater ice is a limit which is approached but not exceeded by cold sea ice and that the reinforcement of brine pockets by Na2SO4.10H2O is either lacking or much less than previously assumed.


2017 ◽  
Vol 17 (14) ◽  
pp. 4388-4393 ◽  
Author(s):  
Wenge Zhu ◽  
Baokai Cheng ◽  
Yurong Li ◽  
Runar Nygaard ◽  
Hai Xiao

Sensors ◽  
2018 ◽  
Vol 18 (3) ◽  
pp. 736 ◽  
Author(s):  
Guodong Zhang ◽  
Yulong Zhao ◽  
Yun Zhao ◽  
Xinchen Wang ◽  
Xueyong Wei ◽  
...  

Author(s):  
Mehmet Mersinligil ◽  
Jean-Franc¸ois Brouckaert ◽  
Julien Desset

This paper presents the first experimental engine and test rig results obtained from a fast response cooled total pressure probe. The first objective of the probe design was to favor continuous immersion of the probe into the engine to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency. The probe is water cooled by a high pressure cooling system and uses a conventional piezo-resistive pressure sensor which yields therefore both time-averaged and time-resolved pressures. The initial design target was to gain the capability of performing measurements at the temperature conditions typically found at high pressure turbine exit (1100–1400K) with a bandwidth of at least 40kHz and in the long term at combustor exit (2000K or higher). The probe was first traversed at the turbine exit of a Rolls-Royce Viper turbojet engine, at exhaust temperatures around 750 °C and absolute pressure of 2.1bars. The probe was able to resolve the high blade passing frequency (≈23kHz) and several harmonics up to 100kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe was also used in a virtual three-hole mode yielding unsteady yaw angle, static pressure and Mach number. The same probe was used for measurements in a Rolls-Royce intermediate pressure burner rig. Traverses were performed inside the flame tube of a kerosene burner at temperatures above 1600 °C. The probe successfully measured the total pressure distribution in the flame tube and typical frequencies of combustion instabilities were identified during rumble conditions. The cooling performance of the probe is compared to estimations at the design stage and found to be in good agreement. The frequency response of the probe is compared to cold shock tube results and a significant increase in the natural frequency of the line-cavity system formed by the conduction cooled screen in front of the miniature pressure sensor were observed.


1962 ◽  
Vol 4 (31) ◽  
pp. 134 ◽  
Author(s):  
F. Loewe
Keyword(s):  

1994 ◽  
Vol 40 (136) ◽  
pp. 566-568
Author(s):  
G. A. Kuehn ◽  
E. M. Schulson

AbstractExperiments have shown that tensile ductility of about 5% or more can be imparted to columnar, saline ice by pre-compressing the material by about 3.5%. This effect is similar to that observed in granular, fresh-water ice and is attributed to the operation of both dislocation creep and diffusion creep within that part of the matrix which recrystallized during the pre-compressive deformation.


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