I'm not sure why you don't want to use META tags... that's the way to do it. You really should use all the tools available to you if you want to accomplish something with your applications.
As far as a PHP function, remember that PHP is a server-side scripting language. It interprets your PHP code on the page, renders HTML, then sends it to the client. After that, PHP no longer has any control over the page. Therefore, you can't refresh with PHP -- you have to use a client-side solution, like Javascript.
This one will reload the page every 10 seconds:
<script type=text/javascript>
// The time out value is set to 10,000 milliseconds, or 10 seconds
setTimeout('document.location=document.location',10000);
</script>
