Recent content by pomekrank

Hi, Say we have fluid A with thermal capacity C_a and fluid B with C_b. If we create a solution with X% of fluid A and (1-X)% of fluid B, is it true that the new thermal capacity of the mixture will be C_new ?= C_a*X + C_b * (1-X) Or it is a case-by-case relationship that depends on the nature...

and how do you quantify it ?

Ok but how is it possible that in case of magnetocaloric material the temperature increases if no energy is added to the system (system = sample) ? You wrote about dipole reorientation, but doesn't it need energy to change orientation ?

Let's make it sample and reformulate the problem. I put a sample of material into a 1T magnetic field. The polarization of the sample thus change, so what is the energy transfert from the permanent magnet to the material ? I mean, how much energy is absorbed ?

I got to say that I don't understand the physics of the process too well. If you put gadolinium in the field, the temperature increases. But where does that energy come from and how do you evaluate it ? I mean, it's not restore to the magnet when the sample is taken away of the field since the...

This magnet is used for magnetic refrigeration where a magnetocaloric material is heated up to produce cold. However, a 1T field produces about ΔT = 2.5 K, which means the energy for enthalpy change is about Q = m*cp*ΔT = (0.25kg)(240 J/kg-K)(2.5) = 250 J. So it makes no sense that I can have...

Hi, I would like to evaluate the required work to create a 1 T field with a permanent magnet. I saw a few formulas on the internet, but I don't know how to use them correctly. The main one are B={{\mu }_{0}}\left( H+M \right) {{W}_{mag}}=\frac{{{B}^{2}}}{2{{\mu }_{0}}}Vol Let's say I know all...

Hello, I have a typical 1D advection problem where a cold fluid flows over a flat plate. I did an energy balance to include conduction, convection and friction loss and I got the PDE's for the fluid and the solid. I used finite differences to solve the system as T(x, t) for both fluid and...

Does CN is ONLY good with heat equation or it's still reliable for similar equation like \frac{\partial T}{\partial t}=\alpha \frac{{{\partial }^{2}}T}{\partial {{x}^{2}}}+\beta \frac{\partial T}{\partial x}

Ok I get the fact that CN is unconditionally stable, but If i can reword my question to make it as easy as possible, if the left side is (1) \frac{\partial T}{\partial t}\approx \frac{T_{i}^{k+1}-T_{i}^{k}}{\Delta t}+O\left( \Delta t \right) or (2) \frac{\partial T}{\partial t}\approx...

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Ok if I do understand, Crank-Nicolson's order in space depends on how you approximate the spatial derivative and temporal is by definition an order of 2 because it's averaged. In my case it's true to say that C-N is O(Δt^2, Δx^2), but irrelevant to say that the order in the left side of the...

Hi, Let's consider the heat equation as \frac{\partial T}{\partial t}=\alpha \frac{{{\partial }^{2}}T}{\partial {{x}^{2}}} In order to have a second accuracy system, one can use the Crank-Nicolson method as \frac{{{\partial }^{2}}T}{\partial {{x}^{2}}}\approx \frac{1}{2}\left(...