I assume $calculationData is an object from a database and the PDF content is stored there as binary data. Then you can do something like this:

Link to a PHP file that loads the content and sends it to the browser.

<a href="show_pdf.php?id=555">

Where id is the id of your calculationData somewhere in the database in this example. You need something to identify it.

show_pdf.php:

<?php
/* load your calculation data here ... */

header("Content-type: application/pdf");
header("Content-Disposition: attachment;filename='mywhateverfile.pdf'");

echo $calculationData->PDF_file;
exit();

In that way you can send the binary data to the browser and telling it with the correct headers, what to do with that data.