National Repository of Grey Literature 10 records found  Search took 0.00 seconds. 
Velocity and Temperature Decay in Turbulent Flow behind Parallel Heat Sources
Antoš, Pavel ; Uruba, Václav
Paper deals with the velocity and temperature field generated by a system of parallel heated wires placed in grid-generated turbulent flow. Development of the temperature field was studied for a number of configurations of grid generator and line heater was investigated experimentally. Decay of the temperature fluctuations was evaluated from thermoanemometry measurements.
Applicability Of The Heat-Transfer Law In Hot-Wire Anemometry
Antoš, Pavel
Paper deals with the heat transfer from the hot-wire to the fluid, namely at low overheats. Various heat-transfer laws for this case have been investigated. The use of generalized form of the Collis-Williams law for common probes at middle and low overheats has been discussed in detail.
CTA measurements at low overheats
Antoš, Pavel
The static dependence of the output anemometer voltage on the gain and the offset voltage of the amplifier was investigated experimentally. The DISA CTA bridge 55M10 was examined. Data were compared to the measurements performed at a Wheatston bridge without any amplifier.
Interpretace měření CTA anemometrem při nízkém žhavení
Antoš, Pavel
The paper deals with an effect of dynamic adjustment on the behaviour of constant-temperature anemometer. The static dependence of the output anemometer voltage on the gain and the offset voltage of the amplifier was investigated experimentally. Applied model of the CTA feedback system fits the behaviour of the bridge satisfactory.
Heat loss of the hot-wire at low overheats
Antoš, Pavel
Collis-Williams cooling law seems not to be suitable for a wide range of the operation wire temperatures. A new form of the cooling law has been proposed for low-overheated wires.
Reference Film Temperature in the Hot-wire Anemometry
Antoš, Pavel
Dimensionless parameters in the cooling law are referred to the reference film temperature. In case of the mean film temperature there is necessary to use a temperature loading factor. There were found such reference temperatures that the loading factor is eliminated.
Assessment of the sensor temperature in HWA
Antoš, Pavel
One of the key parameters in hot-wire anemometry is the temperature of the sensor. The temperature is set on CTA via the resistivity of the hot sensor. Several probes were tested using a variable temperature oil bath. Dependence of the resistivity on the temperature and means of its estimation are the subjects of the paper.
Modification of the theoretical solution of the hot-wire temperature distribution
Antoš, Pavel ; Knob, Martin
Temperature distribution along the wire with respect to non-linear resistivity-temperature relationship and its comparison with the simplified theoretical solution is the subject of the paper.
Influence of the non-linear resistivity-temperature relationship on the mean wire temperature
Antoš, Pavel
Hot-wire temperature is usually calculated by a linear resistivity-temperature relationship instead of much more accurate second order relationship. Effect of the non-linearity on the mean temperature is the subject of the paper.
Influence of the flow temperature on the hot-wire heat transfer
Antoš, Pavel
A set of calibration curves of the hot-wire was observed at various fluid temperatures.Measurements were performed on the special calibration rig. There is a dimensionless expression of the heat transfer in the paper.

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