• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
vadevaman

Whats a good mathematical model for heat transfer?

5 posts in this topic

Well basically I have  one main heat variable wich increases and decreases by its modifyers.
Now the interesting part for me is, that how would I transfer the heat dynamically to another variable?

For a good example, heat transfer from oil to water in cars. The oil Heats up and if the water is colder than the oil, it heats up to the same temperature, but it wont do this instantly. It takes some time to transfer heat from one fluid to another.

If possible Id like to ignore if/else sentences and do it all mathematically, this way it would stay dynamic.

 

So to start things of, obviously I need  a heattransfer variable, so the higher this is the faster the transfer takes place. I'd like to keep this 1.0 at highest, where the heat transfer is almost instant., so a variable of 0.3 would give smoother transfer.
And I also need a cooling variable, so that the heat can be cooled down if its higher than the desired temperature. Same criteria for heating applys to cooling.

As I understand I have to take use of a formula like this:

// decrease
transfer -= (constant + transfer)*transferspeed*dT;
// increase
transfer += (constant - transfer)*transferspeed*dT;

right? But how could I write it as close to a single line code with cooling included ?

 

Edit:

Also how to make it so that the desired heat will also decrease, because its a heat transfer procedure.  As a law of physics theres no such thing as a free lunch.

Thanks!

Edited by vadevaman
0

Share this post


Link to post
Share on other sites

Start by thinking about it as heat energy, not as temperature.

You can get temperature from the internal energy by having the mass and thermal heat capacity of the objects.

The difference in temperature drives a flow of heat energy between the objects.

A thermal resistance slows this flow.

 

It works like Ohms law.  (E=IR)

But with thermal-ness it would be (T = QR)

where T is temperature delta, Q is heat flow, R is thermal resistance.

 

How you calculate R is the crux of how complicated your system is!  For a simple "looks good enough" you can just base it on surface area of the objects in contact with a scaling factor. 

For a more accurate effect, you'd have to deal with things like arriving at a convection coefficient which is brilliantly convoluted to calculate.  For round objects there are some natural logs that show up in the calculation of R.  There are Nussault numbers and Prandl numbers.  You can go nuts here.

 

Your specific example of heat transfer from oil->water is an example of a heat exchanger.

 

If you can be more specific about what you need to accomplish, we can advise you better.

2

Share this post


Link to post
Share on other sites

You may want to use a relatively simple heat transfer simulation.

 

[attachment=21566:heat_transfer.png]

 

Thermal units (BTUs) are driven by temperature differences. I've shown it as linear but it's actually a higher order curve.

 

The oil is at one temperature. Near the radiator wall there's a transfer region whose coefficient is oil dependent. The radiator wall has a coefficient, as does the water.

 

Given oil and water temperatures, setup equations for each transfer region and solve for the temperature at each interface.

1

Share this post


Link to post
Share on other sites
Simple version: The amount of heat transferred per unit of time is proportional to the difference in temperature. The constant of proportionality is what controls how fast the transfer happens.
 
  // Each timestep

  transfer_heat = control_variable * timestep_length * (object_B.temp - object_A.temp);
  object_A.temp += transfer_heat / object_A.heat_capacity;
  object_B.temp -= transfer_heat / object_B.heat_capacity;
Edited by Álvaro
1

Share this post


Link to post
Share on other sites

Depends on the type of heat transfer and how detailed you want. Are you trying to model conduction and convection or radiation as well? Conduction and convection are pretty simple, but radiation takes a bit of code. For a simple model with conduction and convection, the resistive model is a good one.

1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0