-
#1160 by X_RaY on 12 Apr, 2016 17:57
-
X_Ray, just for the heck of it why not try 5.2538 GHz which is the calculated "up-scaled" frequency
For me the confusion was completed since you write the numbers of the dimensions in you sketch was meant to be "cm" (I thought it was in inch). Since you didn't use any units for the dimensions in the sketch below, and for the future, it would be nice to write units in such drawings.
1.8804GHz x 2.794=5.2538 GHz
In addition I don't notice the 5.3..GHz, sorry that was my mistake.
-
#1161 by rfmwguy on 12 Apr, 2016 18:07
-
Nice work, think copper to copper is the best. No loose fibers. Will also act as heatsink so small diameter should stay cooler. Thermal imaging copper is difficult since its so conductive. Mode shapes will have to rely on modeling rather than thermals unless you can drive flir to very narrow thermal range. Keep up the good work. Back to fab for me too. Mounting magnetron on plate today. Later.Also humbly suggest another copper plate on top of them to flatten and press outwards.
Definitely a lot cleaner. Lowes had the copper scouring pads in a different location than the rest of the metal wool. -
#1162 by Monomorphic on 12 Apr, 2016 18:15
-
Are you also planning to paint the end plate(s ? , particularly the non-adjustable big end) with flat-finish black paint (the same way as you did for the side-walls), so that you can scan them (using the same emissivity setting) with the infrared camera to tell the mode shape ?
The mode shape on the adjustable small end may NOT be readily captured because the inner plate will be the one induction heated. The exterior end plate on the small end will not be representative of the inner electromagnetic field in the cavity
That is a drawback from using an adjustable end: it does not allow accurately reading the mode shape on that end (with an infrared thermal camera).
The big end is already painted black. I did that the same time as the rest. definitely won't be able to see the small end-plate, but I think the mode(s) i'm exciting should be apparent by looking at the big end and side walls. -
#1163 by Monomorphic on 12 Apr, 2016 18:21
-
One question, in the horizontal position the tuning apparatus may lead to problems.. Do you use a spring between the inner and the outer end plate? Or did you solve this mechanical problem with another solution?
I could use springs, and I purchased some just for that purpose. The small end-plate is very tight and close-fitting. Right now I simply tighten the three wing nuts equally to pull the small end-plate, lengthening the cavity. I measure the distance the tightening bolts protrude to make sure the small end-plate is parallel with the large end-plate. Right now I can only tune in one direction, and have to push the small end-plate back to it's start position when finished. -
#1164 by Rodal on 12 Apr, 2016 18:30
-
1) Thermal imaging relies on emissivity instead of conductivity.
...Thermal imaging copper is difficult since its so conductive. Mode shapes will have to rely on modeling rather than thermals unless you can drive flir to very narrow thermal range....Also humbly suggest another copper plate on top of them to flatten and press outwards.
Definitely a lot cleaner. Lowes had the copper scouring pads in a different location than the rest of the metal wool.
where Q is the heat flux, ε is the emissivity, σ is the Stefan-Boltzmann constant, and T is the absolute temperature.
Thermal conductivity cannot affect the thermal camera reading, which will capture the temperature difference if it is higher than the camera's threshold. All that thermal conductivity can do is to conduct the heat. The electromagnetic field in the cavity is induction heating certain areas in the copper (according to the specific pattern of the mode shape) and this heat is being transferred by conduction into the non-heated copper.
2) High thermal conductivity and thermal diffusivity of copper will not much affect the induction heating profile while the power is on, if the power is high enough compared to the thermal sink provided by the copper, because induction heating takes place at the speed of light while heat diffuses in the copper at orders of magnitude slower (governed by the thermal conductivity divided by the heat capacity and the density). Hence while the induction heating power is on the thermal camera should be able to capture the induction heated mode shape in Monomorphic's experiment if the power is high enough so that the temperature difference is above the threshold of his thermal camera. (*)
Of course, once the power is off, then the copper will thermally diffuse the heat so that eventually (in seconds) it will be more uniform. So that thermal scanning, has to be done in real time, when the power is on.
3) This is a thermal scan of induction heated copper (from a supplier of induction heating equipment):
I have personally used induction heating equipment (that I designed) in the past to rapidly heat copper from room temperature to over 800 deg F (426 deg C), in copper shells that were several inches thick (a very large heat sink).
__________
(*) induction heating a material is quite different from thermally conducting heat into a material
(**) Fourier’s law of heat conduction predicts an infinite speed of propagation for thermal signals, i.e. a behavior that contradicts the main results of Einstein´s theory of relativity, namely that the greatest known speed is that of the electromagnetic waves propagation in vacuum. Cattaneo introduced the concept of the relaxation time (some people also trace this concept back to Maxwell), as the build-up time for the onset of the thermal flux after a temperature gradient is suddenly imposed on a material. See:
http://waset.org/publications/3892/maxwell-cattaneo-regularization-of-heat-equation
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.16.115&rep=rep1&type=pdf -
#1165 by X_RaY on 12 Apr, 2016 18:41
-
I have to reject this frequency for TE012 using your dimensions. See pics belowX_Ray, just for the heck of it why not try 5.2538 GHz which is the calculated "up-scaled" frequency
For me the confusion was completed since you write the numbers of the dimensions in you sketch was meant to be "cm" (I thought it was in inch). Since you didn't use any units for the dimensions in the sketch below, and for the future, it would be nice to write units in such drawings.
1.8804GHz x 2.794=5.2538 GHz
In addition I don't notice the 5.3..GHz, that was my mistake.
For all geometric dimensions I use units in "mm"in this case!
-
#1166 by Monomorphic on 12 Apr, 2016 18:59
-
A picture of the inside of the cavity that includes the magnetron antenna.
-
#1167 by FattyLumpkin on 12 Apr, 2016 19:29
-
X_Ray, sorry for the confusion over the numbers. It is in metric BD 10.0 cm, Height 8.182 cm and SD 5.682cm
This is the NASA frustum downsized by factor of .2794. As you came see on the EM drive experimental results page TE012 and TM212 were modes reported. The frequency I gave was based on the TE012 mode @1.8804 GHz.---the 5.2538 GHz is merely the factored up frequency of 1.8804 GHz. Ausgezeichnete arbeit! ...looking forward for your final outcome. FL -
#1168 by X_RaY on 12 Apr, 2016 20:08
-
X_Ray, sorry for the confusion over the numbers. It is in metric BD 10.0 cm, Height 8.182 cm and SD 5.682cm
OK please show exactly what you are doing.
This is the NASA frustum downsized by factor of .2794. As you came see on the EM drive experimental results page TE012 and TM212 were modes reported. The frequency I gave was based on the TE012 mode @1.8804 GHz.---the 5.2538 GHz is merely the factored up frequency of 1.8804 GHz. Augezeichnete arbeit! ...looking forward for your final outcome. FL
0.15875m=158,75mm*0.2794=44,35475mm =4.435475cm ≠ 5.682cm
0.2797m=279,7mm*0.2794=78.14818mm =7.814818cm ≠ 8.182cm
0.2286m=228,6mm*0.2794=63,87084mm = 6.387084cm ≠ 10.0cmX_Ray, just for the heck of it why not try 5.2538 GHz which is the calculated "up-scaled" frequency
Where is this factor come from? 0.2794?? 2.794??
1.8804GHz x 2.794=5.2538 GHz
Pease explain in detail what is meant
Maxwell equations are linear. Scale all dimensions down by a factor x, the resonant frequency for a given mode inside of a cavity resonator increases by the same factor.
-
#1169 by Eusa on 12 Apr, 2016 21:26
-
The rendered image of an optimized cavity for gravity guiding standing waves. -
#1170 by Monomorphic on 12 Apr, 2016 21:49
-
The rendered image of an optimized cavity for gravity guiding standing waves.
Can you provide the exact dimensions, including the radius for the spherical end-plates? Also, what frequency? I've done a sweep on a frustum with spherical end-plates, but not one as "wide" as yours. May be interesting to see.
-
#1171 by RotoSequence on 12 Apr, 2016 22:45
-
The rendered image of an optimized cavity for gravity guiding standing waves.
Gravity guiding standing waves, as in standing waves that guide gravity? -
#1172 by FattyLumpkin on 12 Apr, 2016 23:08
-
X_Ray, yes--typo one decimal off so 27.94cm/2.794 = 10 cm, 22.86cm/2.794 = 8.18181...cm =
8.181818...round up to 8.182 cm and 15.875 cm/ 2.794 = 5.681818...round up 5.682cm
The reduction factor of 2.794 was implemented so the frustum would fit in a Cubesat. Sorry for the mix up!
FL -
#1173 by FattyLumpkin on 12 Apr, 2016 23:16
-
X_Ray, you also highlighted the two different modes: TE012 and TM212 ---I did know this but it was argued in several pages back (of this thread) that TM212 was contraindicated. Yes, as you can see in EM drive experimental results TM212 was noted in different frequencies. FL
-
#1174 by Monomorphic on 12 Apr, 2016 23:17
-
One question, in the horizontal position the tuning apparatus may lead to problems.. Do you use a spring between the inner and the outer end plate? Or did you solve this mechanical problem with another solution?
Updated your image so the tuning section design is more clear.
-
#1175 by Eusa on 13 Apr, 2016 04:23
-
The rendered image of an optimized cavity for gravity guiding standing waves.
Can you provide the exact dimensions, including the radius for the spherical end-plates? Also, what frequency? I've done a sweep on a frustum with spherical end-plates, but not one as "wide" as yours. May be interesting to see.
These are inner dimensions of the cavity. It's filled up with inert air, calculatory speed of light: 299 700 km/s,
The frequency could be multiple of 484,9514563 MHz i.e. 2,424757282 GHz or 4,849514563 GHz TE-mode. -
#1176 by Eusa on 13 Apr, 2016 04:34
-
That's right. The hypothesis is that a normal spherical gravity field is in standing waves. In the cavity there is an artificial gravity field if only the electric component with harmful inductions and coherence guidance to magnetic flux could be eliminated.The rendered image of an optimized cavity for gravity guiding standing waves.
Gravity guiding standing waves, as in standing waves that guide gravity? -
#1177 by Eusa on 13 Apr, 2016 04:55
-
Eusa, are your dimensions in mm, cm? Thank you for your input. I did not do calculations based on speed to guess as I am unsure of a proper equation.
My dimensions are in mm. -
#1178 by Chrochne on 13 Apr, 2016 08:28
-
Mr. Mike McCulloch new paper "Testing quantised inertia on the emdrive"
http://arxiv.org/abs/1604.03449
Apologies if it was already posted.
-
#1179 by hk524khk524k on 13 Apr, 2016 09:03
-
I'm intertested in the EMdrive. By the way, is there any experimental result that EM drive generates thrust to the opposite direction which is ignoring the theoretical expectation?
