Self-regulating proportionally controlled heating apparatus and technique

A self-regulating proportionally controlled heating apparatus and technique is provided wherein a single electrical resistance heating element having a temperature coefficient of resistance serves simultaneously as a heater and temperature sensor. The heating element is current-driven and the voltage drop across the heating element is monitored and a component extracted which is attributable to a change in actual temperature of the heating element from a desired reference temperature, so as to produce a resulting error signal. The error signal is utilized to control the level of the heater drive current and the actual heater temperature in a direction to reduce the noted temperature difference. The continuous nature of the process for deriving the error signal feedback information results in true proportional control of the heating element without the necessity for current-switching which may interfere with nearby sensitive circuits, and with no cyclical variation in the controlled temperature

Active control of laminar-turbulent transition

Instability waves, commonly called T-S waves, can be introduced in a laminar boundary layer by periodic heating of flush-mounted heating elements. Experiments have demonstrated that nearly complete cancellation of a T-S wave excited in this way can be achieved by using a second downstream heating element with a suitable phase shift. As one application of the technique, a single element together with a feedback loop activated by measured wall shear stress has been used to reduce the amplitude of naturally occurring laminar instability waves. A significant increase in the transition Reynolds number has been achieved

Thermocouple, multiple junction reference oven

An improved oven for maintaining the junctions of a plurality of reference thermocouples at a common and constant temperature is described. The oven is characterized by a cylindrical body defining a heat sink with axially extended-cylindrical cavity a singularized heating element which comprises a unitary cylindrical heating element consisting of a resistance heating coil wound about the surface of metallic spool with an axial bore defined and seated in the cavity. Other features of the oven include an annular array of radially extended bores defined in the cylindrical body and a plurality of reference thermocouple junctions seated in the bores in uniformly spaced relation with the heating element, and a temperature sensing device seated in the axial bore for detecting temperature changes as they occur in the spool and circuit to apply a voltage across the coil in response to detected drops in temperatures of the spool

Tidal Heating Models for the Radii of the Inflated Transiting Giant Planets WASP-4b, WASP-6b, WASP-12b, and TrES-4

In order to explain the inflated radii of some transiting extrasolar giant planets, we investigate a tidal heating scenario for the inflated planets WASP-4b, WASP-6b, WASP-12b, WASP-15b, and TrES-4. To do so, we assume that they retain a nonzero eccentricity, possibly by dint of continuing interaction with a third body. We calculate the amount of extra heating in the envelope that is then required to fit the radius of each planet, and we explore how this additional power depends on the planetary atmospheric opacity and on the mass of a heavy-element central core. There is a degeneracy between the core mass $M_{\rm core}$ and the heating $\dot{E}_{\rm heating}$. Therefore, in the case of tidal heating, there is for each planet a range of the couple $\{M_{\rm core},e^2/Q'_p\}$ that can lead to the same radius, where $Q'_p$ is the tidal dissipation factor and $e$ is the eccentricity. With this in mind, we also investigate the case of the non-inflated planet HAT-P-12b, which can admit solutions combining a heavy-element core and tidal heating. A substantial improvement of the measured eccentricities of such planetary systems could simplify this degeneracy by linking the two unknown parameters $\{M_{\rm core},Q'_p\}$. Further independent constraints on either of these parameters would, through our calculations, constrain the other.Comment: Accepted in ApJ; 17 pages, 3 figures, 6 tables (emulateapj format); expanded explanatory tex

Low power heating element provides thermal control during swaging operations

Low power, cylindrical heating element in a swaging anvil assembly heats the material being worked on. The increased ductility of heated material results in crack-free deformation

Thermocouple for heating and cooling of memory metal actuators

A semiconductor thermocouple unit is provided for heating and cooling memory metal actuators. The semiconductor thermocouple unit is mounted adjacent to a memory metal actuator and has a heat sink attached to it. A flexible thermally conductive element extends between the semiconductor thermocouple and the actuator and serves as a heat transfer medium during heating and cooling operations

Textile elements for car seat to improve user’s driving comfort

The main motive for this research is the desire for the improvement of the automotive seat occupant’s comfort by designing a heating mat prototype made with distance knitting technology with heating elements. In this study, the following design steps were undertaken: preparation of the trajectories of heating cables, calculating the resistance needed to obtain the estimated power of the whole mat, testing of available electroconductive yarns to assign the most suitable yarn to a specific design, preparation and testing of five heating mat prototypes with three various trajectories of the heating element. All samples were evaluated with the same criteria in order to find the most promising design. After all experiments, a prototype with stainless-steel BekaertVR VN 12.2 coated yarn as a heating element, showed the best performance, especially in combination with distance knitted fabric thanks to its internal construction. This work demonstrates that a three-dimensional distance knitted fabric with a heating element introduced into its structure will ensure the physiological sitting comfort. After further subsequent studies, the proposed method can be adapted for industrialisation by using warp knitting machines, thus improving the quality and durability of the heating mat