Wordpress get Page content By Page ID

<?php
if(!function_exists('getPageContent'))
 {
  function getPageContent($pageId,$max_char)
  {
   if(!is_numeric($pageId))
   {
    return;
   }
   global $wpdb;
   $nsquery = 'SELECT DISTINCT * FROM ' . $wpdb->posts .
   ' WHERE ' . $wpdb->posts . '.ID=' . $pageId;
   $post_data = $wpdb->get_results($nsquery);
   if(!empty($post_data))
   {
    foreach($post_data as $post)
    {
     $text_out=nl2br($post->post_content);
     $text_out=str_replace(']]>', ']]>', $text_out);
     $text_out = strip_tags($text_out);
     return substr($text_out,0,$max_char);

    }
   }
  }
}
?>

How to Call function getPageContent?

<?php echo getPageContent(11,150); //First parameter is PAGE ID and second is number of words displayed. ?>