Recent content by whiteskulleton

I just ran the test again but this time filmed it. Below is the raw video. I don't have time right now to analyze and extract the data. It's filmed at 240 fps but I like to upload it and slow it down by 8x using this website: https://ezgif.com/video-speed Also, attached is a pdf of the...

I just ran another test in the same exact geometry conditions as before. The starting pressure was at -510 mmHg or 33330 Pa(abs). However I stopped the flow suddenly at 57462 Pa(abs). It then dropped to a final pressure of 54929 Pa(abs). Since the change in pressure occurs in a closed system, it...

This sort of brings me to the next real world application. We are testing the holding force of suction cups using this tank. The standard vacuum pressures that we recommend should be above 40% vacuum or ##p<60795\,\mathrm{Pa(abs)}##. We test the suction cups by connecting the tank to a pressure...

Here is the procedure that I used to get the governing equation: From post #24 and the equation from the Wikipedia article $$\dot{m}(t)=\left\{\begin{matrix} 0.007902C_d & \textrm{if } 0\leq t\leq 1.8963\\ C_dA \sqrt{2\, \rho_1\, p_{atm}\left ( \frac{\gamma}{\gamma-1} \right )\left [ \left (...

Your starting to reach the limits of my knowledge here with that first-order nonlinear differential equation. What I'm pretty sure of, is that the flow is a choked flow from ##p(0)<p<53530.58\mathrm{Pa}## which means that the mass flow rate is constant and so $$\dot{m}=C_dA\sqrt{\gamma...

Let's try this again. $$\bar{\rho}=\frac{M}{2R}\left[\frac{p_{atm}}{T_{atm}}+\frac{p}{T}\right] $$ Since ##\bar{\rho}## is the average density, then we need to plug in the initial conditions ##p=33.463\mathrm{ kPa}## and ##T=295.372\mathrm{ K}##...

Just found the latex info, lol. So you are proposing the following equation $$(p_{atm}-p)=\frac{k}{2\bar{\rho}}\frac{\dot{m}^2}{A^2}$$ Where $$\bar{\rho}=\frac{M}{2R}\left[\frac{p_{atm}}{T_{atm}}+\frac{p}{T}\right]$$ I'm assuming ##T## is the final temperature and ##p## is the initial pressure...

I used this website: https://planetcalc.com/5992/ It's a very quick way to run different regressions to determine the best one. X-Data: 0.013020875 0.108853125 0.17968575 0.308333375 0.475516125 0.592181625 0.688014 0.79634625 0.867178875 0.983844375 1.067176875 1.183842375 1.254675 1.375507125...

I just discovered something very interesting. I opened up my Fundamentals of Fluid Mechanics Seventh Edition textbook from college, turned to the last chapter about compressible flow and low and behold, all the equations that I just listed out were there. 🤦‍♂️ That would have helped...

I finally was able to simplify the equation down: Now, you did also tell me to add gamma to the equation and simplify. Thus,

So here are my equations And here are the initial conditions You can solve Eq. 2,4,7 outright getting: I then solve for n in equation 5. Plug that into equation 6. I then plug equation 6 into equation 3 and also plug equation 1 into equation 3 and then solve for the final temperature. I...

Thanks for the reply. I'm guessing that this diagram is a correct representation of the system? Based on the first law of thermodynamics you get Since you are saying that I should assume that it is adiabatic, that means that there is no heat transfer into the system so Q=0. Since there is no...

I have a vacuum tank at work that I am trying to determine the flow rate and pressure curve of when I open up the tank and I just cannot figure these equations out. Environment: average office space Atmospheric pressure: 29.92 inHg (per weather information) Temperature: 72°F Tank info...